Texas Register Yolu-re~ 12, Numbsr 52, Jnly 1q 1987 Adopted Rules TITLE 25. HEALTH _ SERVICES _ Part I. Texas Department of _ Health Chapter 301. Wastewater Surveillance and Technology Construction Standazds for Private Sewage Facilities ~k23 TAC §§301.11-301.13 The Texas Department of Health adopts the repeal of §§301.11-301.13 arid new §§301.11.301.17. New §§301.11-301.17 are adopted with changes to the proposed text published fn the January 13, 1987, Issue of the Tezas Register (12 TexReg 115). The adoption of the repealed sec- tions and the new sections update, clarity, and modify the construction standards for on-site sewerage systems. The new sections will reduce exposure to disease causing agents,lncrease aesthetlca of habitation, reduce lost wages and time due to Illness, and reduce medical bills. The new sections cover general pro- cedurea and Inforrnatlon, definitions, gen- eral environmental requlremehts, autho- rlty of the department to regulateorrsite sewerage facilltle0. relations with other governmental entitles, design approvals of on•slte sewage disposal systems, de- sign standards for sewage processing systems, design standards for effluent disposal systems, disposal alternallves, on•elte system maintenance and water conservation, unsatisfactory dlaposal . systems, and tables and figures. The new sections contain more detailed descrlp• tlons of technological advancements In on-alto sewage treatment and disposal, clarifying language, changes In minimum sewage dlaposal alto areas, and the use of mandatory language In order to provide statewide consistency In application. The department held six public hearings throughout the state on the proposed sec- tions. Over 240 Individuals, representing either themselves or groups, attended hearings In Austin, Houstori,'LLbbot?c, trend Pralrle, Tyler, and Harlingen. In ad- dltbn, wrlttencomments were submitted directly to the department. NOTE: THESE RULES BECOME EFFECTIVE ON JANUARY 1, 1988, Moat of the comments addressed three CONTRARY TO THE DATE PUBLISHED IN THIS REGISTER. maJor areas: the alterations In lot size In !2 Tex:~2:g Id?r5 July !0, 1987 Tezas Register ~ 1 §301.11(fx4); the cost effectiveness of dual compartment septic tanks In §301.12(ax4); and the need for the Inclusion of a grartd- father clause In §301.11(4x0). The follow- ing paragraphs contain asummary of the comments In these three areas. Regarding §301.11(}x4), the revised ~~an- dards make mandatory a lot size of one• half for all platted sutxflvlslons served by a public water supply. in platted subdivl- slons served by individual water systems, lot size Is required to be one acre. Public statements as well as written comments were strongly divided on this Issue. Representatives of various county, municipal, and river authorities strongly supported the Increase in lot size. Many even requested greater square footage In specific areas of the state; for example, around water bodies which should require buffer zones between shore and septic tank. These commentors supported the need for available land for a duplicate system should the initial system fall. They strongly emphasized the public health dangers of failed systems and viewed an Increased lot size, consistent throughout the state, es an excellent means to avoid health problems. In addition, they con- sidered Increased lot size as an insurance policy for fhe homeowner should a sys• tam fall. The disaster of a failed system with no available area for a duplicate system can be financially devastating to many homeowners. Speciflcaliy, commenters wished assurances that easements to various utility entities would be excluded from the lot size requirement. Net versus gross lot sizes should be clarified in these Instan• ces. The department has clarified this distinction. Much discussion from government of• facials centered on mobile home parks. Of- ficlals strongly expressed the desire to treat mobile homes as conventional hous- ing. Specific changes were requested In the formula for computing the estimated gallons of sewage flaw from mobile homes per day. The department agrees with this need. Moblie homes will be treated as permanent residences. Generally, commenters representing local pubtlc entities emphasized the consls• tent, prevailing need to protect public health. Although Increase In lot size might be more expensive to the landowner Ini• flatly, the long run health protections and insurance to case of Initial system !allure will compensate for the cost. In contrast, land developers and reactors were~vocally opposed to Increases in lot size. Their objections centered around two major Issues. First, these commen- ters complained that Increased lot size would price many prospective homeown• ere out of the market. Larger plots requha greater expense and this, In turn, would contribute to the already hard hit Texas Second, commercial representatlvea ob- jected to the standards making lot size uniform around the state. Many com- mented that the state was far too large and far too diverse geologically and cli- matically to make the requirement of a single lot size practical. For example, a one-half acre lot is excessive In west Texas where a dry climate could make smatter lots safer. Several commenters suggested that a formula based on cll- matlcand geologic facfors be devised to provide for the state's diverse nature. Em- phasis by these commenters was placed on allowing local authorities to determine the needs of their area- If ail counties had septic tank orders, there would be no need for standards to make mandatory re- quirements for tot sizes. Comments taken from tank manufac- turers and system Installers were mixed. One Installer heartily supported an In- crease in tot size. He felt that the expart- slon will allow him more room to work to maintain the system on the lot. On the other hand, another Installer felt that the need for land area for an alternate system was unnecessary. He felt it would be easier to dig out a malfunctioning system and Install a new one than to allow for the provision of land area for an alternate system. A number of letters opposing the Increase in lot size were rece(ved from Individuals in extreme south Texas. All writers Iden- tified themselves as low Income. They contended that eons-halt acre lot restrlc- tion would deprive them of home owner- shipbecause of their limited assets. After carefully weighing remarks from commen- ters both In public hearing and through correspondence, this department will maintain lot sizes as they appeared In the proposed secflons. As earlier stated, the most important stogie cause of health hazards resulting from felled septic tanks is the dens)ty of residences. Density of population and pubtlc health danger di- rectly relate to lot size. The department acknowledges that the question of lot size !s controversial. However, the department has attempted to find a middle ground between the dis- parate points of view expressetl by com- menters. While the department acknowledges the possibility of Increased costs for home- owners, It views the protection of public health-Including both the homeowner's and his neighbor's health-as the over- riding concern on the tot size question. Regarding §301.12(ax14), on the whole, city-county health officials had no com- plaints concerning the new dual tank re- qulrement.One official felt that It would be no major difficulty to tank manufac- turers since two existing tanks could simply be Installed In series. This practice could also reduce any Inventory of single comgartment tanks !or those mancfac Ttte moss vociferous statements on dual compartment tanks came from septic tank manufacturers and installers. These comments were primarily opposed to the concept. The major objections came from single compartment manufacturers who felt that they faced costly retooling ex- penses before they could produce [he newly required dual tank. However, several manufacturers felt that two single tanks In series would solve any problems with- out costly retooling expense. If retooling was deemed necessary, this method would provide the necessary time. The department agrees with 4his final assessment and has retained the dual compartment requirement. Regarding §307.1 t(4xD), commenters strongly recommended a grandfather clause to cover all previously platted sub- divlslons which do not meet lot size re- quirements, The department agrees with the need for such an addition and has added §301.t1(4xD) to cover the question. Numerous other comments addressed spa cific Items in the secflons such as technlcai language, consistency of ter- minology, clarification of meaning, and grammar and style. Where appropriate, the department accepted recommenda- tions In these areas and made changes in all of the proposed rules. The names of those making comments are listed as follows. Bazar County Public Works Department; AustlnTravis County Health Department; EI Paso City-County Health Dlstrlct; tower Colorado River Authority; Trinity River Authority of Texas; Dallas County Health Department; Tarrant County Health De- partment; Clty of Baytown; Galveston County Health Dlstrlct; David L. Lltke, R.S., Comal County Sanitarian; Brazos River Authority; Fort Worth Water Depart- ment Gregg County Health Department; Taxes Water Development Board; The County of Burnet; Bandera County; Ed- wards Underground Water Dlstrlct Texas Agricultural Extension Service; City of West Lake Hllis; Jimmy L. Doyle, Fannin County Judge; City of Waco; County of Kendall; United States Department of Agriculture Soll Conservation Serv(Ce; San Marcos•Hays County Health Depart- ment; Angelina County and Cities Health Dlstrlct; Robert Morriss, Incorporated, Consul2ing Engineers; Ken Muller, Boer- ne; Clarence J. Spangler, Tecon Proper- tlas, Incorporated, Dallas; Harold Hammer, Hammer Enterprises, Mabank; G. G. Gale, Jc, Gale Real Estate, San An- tonio; Double Diamond, Incorporated; Texas Resort Company; Masters and As- sociates Land Planners, Wbbock; J. H. Nears, Jr., Stephens Development Cor- poraflon, Mount Pleasant; T. G. Hyde, Texas Realty, Incorporated, Mabank; Ronal C. Massey, Mabank; J. G. Boyles, Eastern Land Company, Dallas; Texas Assouation of ~~iiders; Homo and Apart- ., o ...- ~ ==-gcr_,a±ion 9r rvfetrePOli- r_ ~~'S.~P~ )lj~ 2 tan Dallas; John Heaton, Concrete Products, Incorporated, Hewitt; Robert C. Fischer, Wallis Concrete, Incorporated; Bob L Meinzer, HIII Country Concrete Pro- ducts, Incorporated, Kyle; Donald F. Walker, Precast Concrete Products Com- pany, Bandera; Ruben Delgado, Delgado Concrete. Products, San Antonio; C. P. Shumann, Acme Service, Company, San Antonio; Robert B. Mayer, American Manufacturing Company, Manassas, Vir- ginia; Jae D. McNeil, Hancor, Incor- porated, Findlay, Ohlo; Michael S. Price, NORWECO, Norwalk, Ohio; J. Thomas Joyce, Cook-Joyce, Incorporated, Austin; John Bauer, Nayadlc Sciences, Clarks Summit, Pennsylvania; K. W. Brown, Texas A&M University; Arthur W. Nagel, Boerne; United Farm Workers of America AFL-CIO; Richard Delgado, San Antonio; Robert Delgadq San Antonio; Virginia Lopez, San Juan; Juanita Tovias, San Juan; Angelica Perez, San Juan; Diane M. Hernandez, San Juan; Antonio Barron, San Juan; Moricelo Ramos, Donna; Lucldalia Zabala, Alamo; Lupita Rangel, Donna; Josefino eecerre, San Juan; EIvIa Tovias, San Juan; Maria Hernandez, San Juan; Teresa Tovias, San Juan; G. L. Martinez, San Juan; Martin Tovias, San Juan; Bertha Reyes, Alamo; Pedro Negrete, Pharr; Mario Ramirez, Pharr; Josefina Mendoza, Alamo; Jose Lopez, San Juan; Rita Escobedo, Mission; Eduardo Garcia, Donna; Guadalupe Ne- grete, Pharr; Alicia Nabejas, Pharr; Jose Torres, Pharr; Marla Gomez, Pharr; Maria Guadalupe Ortiz, Pharr; Francisco Ortiz, Jc, Pharr, Zeferlno M. Ortiz, Pharr, Severo Rodriguez, Pharr, Martina Rodriguez, Pharr, Juan A. Garcia, Mission; Francisco Camacho, Mission; Juan J. Campos, Mis- sion; Pedro Campos, Mission; Federico Garza, Mission; Victoria Garcia, McAllen; Andre Moreno, Mission; Edwin Kubena, Arrow Septic Company, San Antonio; John McClellan, Southwest Water Service, Flint; Bob Carlile, Cariile d Associates, In- corporated, Collage Station; Brazos Coun- ty Health Department; Jim Boyles, Eastern Land Company, Dallas; BoD Hop- per, Lake Medina Development, Bandera; Gene Juby, Universal Industries; Garry Luker, Cranbury Land Company, Cran- bury; RlchardEdge, Edge Septic Systems, Kendaila; Robert V. Hardwick, Tecon Con- struction, Dallas; Dean Weaver, Victoria Precision, Victoria; O. David Graham, South Texas Wastewater Incorporated, Boerne; W. B. Lloyd; Lloyd Company, Sen Antonio; Chambers County; Brezorla County; Montgomery County Health De• partment; Halls County; Fort Bend Coun- ty; Wbbock Health Department; Gary Hyde, Mabank; Angelina County Health Department; City of Fort Worth Health Department; Gene Pettey, Hancor, Incor- porated, Yoakum; Hunt County; Hldaigo County; Cameron County; San Patricio County Health Department; Don Phillips, J. D. Concrete Unit Step Company, Corpus Christi; 8. Chechere, A S R Septic Tank Servlc2, Corpus Chrlstl. none ci ih2 comrnen~ars ~.vere against ;he 12 TezRe,~ 222,Y Julr !0. l93' proposed sections In their entirety; however, a number of commenters offered objections, suggestions, and comments as outlined in the summary of contents. The repeals are adopted under Texas Civil Statutes, Article 4477.1, §§12, 19, 20, and 23-25, which authorize the Texas Boartl of Health to adopt rules covering on-site sewerage facllltles. This agency hereby certifies that the rule as adopted has been reviewed by legal counsel and found to be a valid exercise of the agency's legal authority. laeued In Austin, Taxes, on June 30, 1987. TRD-8705390 Roben A. Maclean, M.0. Deputy Commissioner Profesalonal Services Texas Department of Health Effective date: July 23, 1997 Proposal publication date: January 13, 1987 For further Infortnatlon, please call (512) 458-7238. ~ ~ ~ Construction Standards for On- Site Sewerage Facilities *25 TAC §§301.11-301.17 The Texas Department of Health adopts the repeal of §§301.11-301.13 and new §§301.11-301.17. Naw §§301.11-301.17 are adopted with changes to the proposed text published In the January 13, 1987, Issue'of the Texas Register (12 TexReg 115). The adoption of the repealed sec- tlonsand the new sections update, clarify, and modify the construction standards for on-site sewerage systems. The new sections reduce exposure to disease causing agents, Increase aesthetics of habitation, reduce lost wages and time due to Illness, and reduce medical bills. The new sections cover general pro- cedures and Information, definitions, gen- eralenvironmental requirements, authori- ty of the department to regulate on•site sewerage facllltles, relations with other governmental entltiea, design approvals of on-site sewage disposal systems, de- sign standards for sewage processing systems, design standards for effluent disposal systems, disposal alternatives, on-site system maintenance and water conservation, unsatisfactory dleposai systems, and tables and figures. The new sections contain more detailed descrip- tions of technological advancements in on-site sewage treatment and disposal, clarifying the language changes In min(mum sewage disposal site areas, and the use of mandatory language in order to provide statewide consistency In ap- plication. The d~apartment held six public hearings throughout the state on the proposed sec- el. ..,. , - .c ,na ~ y.C gyp... _ -. T2zas ?in~;•; s; -^ 3 hearings In Austin, Houston, Lubbock, Grand Prairie, Tyler, and Harlingen. In ad- ditlon,written comments were submitted directly to the department. Most of the comments addressed three major areas: the alterations In lot size in §301.11(fx4); the cost effectiveness of dual compartment septic tanks in §301.12(a)(4); and the need for the inclusion of agrand- fatherclause In §301.11(4)(0). The follow- ing paragraphs contain a summary of the comments in these three areas. Regarding §301.11(f)(4), the revised stan• Bards make mandatory a lot size of one• half acre for all platted subdivisions served by a public water supply. In plat- ted subdivisions served by individual water systems, lot size is required to be one acre. Public statements as welt as written comments were strongly divided on this Issue. Representatives of various county, municipal, and river authorities strongly supported the Increase in lot size. Many even requested greeter square footage In specific areas of the state; for example, around water bodies which should require buffer zones between shore and septic lank. These commenters supported the need for available land for a duplicate system should the Initial system fait. They strongly emphasized the public health dangers of felled systems and viewed an Increased lot size, consistent throughout the state, as an excellent means to avoid health problems. In addition, they con- sidered Increased lot size as an insurance policy for the homeowner should a sys- tem fail. The disaster of a failed system with no available area for a duplicate system can be financially devastating to many homeowners. Specifically, commenters wished assurances that easements to various utility entitles would be excluded from the lot size requirement. Net versus gross lot sizes should be clarified in these In- stances. The department has clarified this distinction. Much discussion from government of- ficialscentered on mobile home parks. Of- ficials strongly expressed the desire to treat mobile homes as conventional hous- ing. Specific changes were requested in the formula for computing the estimated gallons of sewage flow from mobile homes per day. The department agrees with this need. Mobile homes will be treated as permanent residences. Generally, commenters representing local public entities emphasized the consis- tent, prevailing need to protect public health. Although increase in lot size might be more expensive to the landowner in- Itlally, the long run health protections and Insurance in Case of initial system failure will compensate for the cos' In ccntrast, land developers and reactors =.. - - ;. ~ _.'.=eS it lot two major Issues. First, these com- menters complained that Increased lot size would price many prospective home- owners out of the market. larger plots re- quire greater expense and this, in turn, would contribute to the already hard h(t Texas economy. Second, commercial representatives ob- jected to the standards making lot size uniform around the state. Many com• mented that the state was far too large and far too diverse geologically and climatically to make the requirement of a single tot size practical. For example, a one-half acre lot is excessive in west Texas, where a dry climate could make smaller lots safer. Several commenters suggested that a formula based on clima• tic and geologic factors ba devised to pro- vide for the state's diverse nature. Em- phasis bythese commentors was placed on allowing local authorities to determine the needs of their area. If ail counties had septic tank orders, there would be no need for standards to make mandatory re- quirements for lot sizes. Comments taken from tank manufac• turers and system installers were mixed. One Installer heartily supported an in- crease in lot size. He felt that the expan- sion would allow him more room !o work to maintain the system on the lot. On the other hand, another installer felt that the need for land area for an alternate system was unnecessary. He felt it would be ea- sier to dig out a malfunctioning system and Install a new one than to allow for the provision of land area for an alternate system. 4 number of letters opposing the Increase n lot size were received from individuals n extreme South Texas. Afi writers Iden- tified themselves as law Income. They ;ontended that aone-half acre lot restrtc- :lon would deprive them of home owner- ship because of their limited assets. 4fter carefully weighing remarks from ;ommenters both in public hearing and through conespondence, this department will maintain tot sizes as they appeared ~n the proposed sactlons. As earlier Mated, the most Important single cause if health hazards resulting from felled septic tanks Is the density of residences. Density of population and public health ]anger directly relate to lot size. The department acknowledges that the question of lot size Is controversial. However, the department has attempted to find a middle ground between the disparate points of view expressed by commenters. While the department acknowledges the possibility of Increased costs for homeowners, it views the protection of public health, Including both the hcmoowner's and his neighbor's health, as the cverrd!~~,g cen~ern on the lot size Regarding §301.12(a)(tA), ort the whole, city-county health officials had no com- plaints concerning the new dual tank re• quirement. One official felt that It would be no major difficulty to tank manufac- turers 91nce two existing tanks could simply be Installed in series This practice could also reduce any Inventory of single compartment tanks for those manufac- turers who wish to retool. The most vociferous statements on dual compartment tanks came from septic tank manufacturers and installers These comments were primarily opposed to the concept. The major objections came from single compartment manufacturers who felt that they faced costly retooling ex- penses before they could produce the newly required dual tank. However, several manufacturers felt that two single tanks in series would solve any problems wlth• out costly retooling expense. If retooling was deemed necessary, this method would provide the necessary time. The department agrees with the reasons given by the latter commenters and has not changed the section. Regarding §301.11(4)(D), commenters strongly recommended a grandfather clause to cover all previously platted sub- divisions which do not meet lot size re- quirements. The department agrees with the need for such an addition and has added §301.11(4)(D) to cover the question. Numerous ocher comments addressed specific Items in the sections such as technical language, consistency Of ter- minology, clariflcatlon of meaning, and grammar and style. Where appropriate, the department accepted recommend~- tlons in these areas and made changes in all o/ the proposed sactlons. The names of those making comments are 8exar County Public Works Department; AustlnTravls County Health Department; EI Paso City-County Health Dlstdct; Lower Colorado River Authority; Trlnlty River Au- thority of Texas; Dallas County Health Department; Tarrant County Health De- partment; Clty of Baytown; Galveston County Health District; David L Utke, R.S., Comal County Senltarian; Brazos River Authority; Fort Worth Water Depart- ment;Gregg County Health Department; Texas Water Development Board; Tha County of Burnet; Bandera County; Ed- wards Underground Water District; Texas Agricultural Extension Service; Clty of West lake Hills; Jimmy L Doyle, Fannin County Judge; Ctty of Waco; County of Kendall; United States Department of Agrtculiure Soll Conservation Service; San Marcos-Hays County Health Depart- meng Angelina County and Cities Health District; Robert Morriss, Incorporated, Consulting Engineers; Ken Muller, Boer- ne; Clarence J. Spangler, Tecon Proper- ties, Incorporated, Dallas; Harold Hammer, Hammer Enterprises, Mabank; G. G. Gale, Jr., Gale Real Estate, San An- tonio; Double Diamond, Incorporated; ?axes Resort Company; Masters and ~ .-fdnpted Rules .4. Associates Land Planners, Lubbock; J. H. Nears, Jr., Stephens Development Cor- poration, Mt. Pleasant; T.G. Hyde, Texas Reality, Incorporated, Mabank; Ronal C. Massey, Mabank; J. G. Boyles, Eastern Land Company, Dallas; Texas Association of Builders; Home and Apartment Build- ers Association of Metropolitan Dallas; John Heaton, Concrete Products, Incor- porated, Hewitt; Robert C. Fischer, Walils Concrete, Incorporated; Bob L. Melnzer, HIII Country Concrete Products, Incor- porated, Kyla; Donald F. Walker, Precast Concrete Products Company, Bandera; Ruben Delgado, Delgado Concrete Pro- ducts, San Antonio; C. P. Schumann, Acme Service, Company, San Antonio; Robert B. Mayor, American Manufacturing Company, Incorporated, Manassas, Virginia; Joe D. Mc Nall, Hancor, Incor- porated, Findlay, Ohlo; Michael S. Price, NORWECO, Norwalk, Ohlo; J. Thomas Joyce, Cook-Joyce, Incorporated, Austin; John Bauer, Nayadic Sciences, Clarks Summit, Pennsylvania; K. W Brown, Texas A&M Un(verelty; Arthur W Nagai, Boerne; United Farm Workers of America AFL-CIO; Richard Delgado, Sen Antonio; Robert Delgado, San Antonio; Virginia Lopez, San Juan; Juanita Tovias, San Juan; Angelica Ferez, San Juan; Diane M. Hernandez, San Juan; Antonio Barron, San Juan; Moricelo Ramos, Donna; Wcidalia Zabala, Alamo; Wpita Rangel, Donna; Josefino Becerra, San Juan; Elva Tov(as, San Juan; Maria Hernandez, San Juan; Teresa Tovias, San Juan; G. L. Martinez, San Juan; Martin Tovias, San Juan; Bertha Reyes, Alamo; Pedro Negrete, Pharr; Marto Ramirez, Pharr; Joseflna Mendoza, Alamo; Jose Lopez, San Juan; Rita Escobedo, Mission; Eduardo Garcia, Donna; Guadalupe Ne- grete, Pharr; Allele NabeJas, Pharr; Jose Torres, Pharr; Marla Gomez, Pharr; Maria Guadalupe Ortiz, Pharr; Francisco Ortiz, Jr., Pharr, Zefertno M. Ortiz, Pharr; Severn Rodriguez, Pharr; Martina Rodriguez, Pharr, Juan A. Garcia, Mlsalon; Francisco Camacho, Mission; Juan J. Campos, Mis- sion; Pedro Campos, Mlsslon; Federico Garza, Mlaslon; Vlctorla Garcia, McAllen; Andre Moreno, Mission; Edwin Kubena, Arrow Septic Company, San Antonio; John McClellan, Southwest Water Service, Flint; Bob Cartite, Carllle 8 Associates, In- corporated, College Station; Brazos Coun- ty Health Department; Jlm Boyles, Eastern Land Company; Bob Hopper, lake Medina Development, Bandera; Gene Juby, Universal Industries; Garry Luker, Cranbury Land Company, Cran- bury; Richard Edge, Etlge Septic Systems, Kendalia; Robert V. Hardwick, Teton Con- struction, Dallas; Dean Weaver, Victoria Precision, Vlctorla; O. David Graham, South Texas Wasfewater Incorporated, Boerne; W. B. Lloyd, Lloyd Company, San Antonio; Chambers County; Brazoria County; Montgomery County Health De- partment; Harris County: Fort Bend Coun- ' ty; Wbbock Health Department: Gary Hyde, Mabank; Angelina County Health Department; City of Fort Worth F:ealth J~Ip ID, 19R? /? TezReg ?3]9 Department; Gene Pettey, Hancor, Incor- porated, Yoakum; Hunt County; Hidalgo County; Cameron County; San Patrlc!o County Health Department; Don PhI11Ips, J. Q Concrete Unlt Step Company, Corpus Christi; B. Chechere, A 8 R Septic Tank Service, Corpus Chrlatl. None of the commenters were against the proposed sections In their entirety; how- ever, anumber of commenters offered oa )actions, suggestions, and comments as outlined In the summary of comments. The new sections are adopted under Texas CIvII Statutes, Article 4477.1, §§12, 19, 20, and 23.25, which authorize the Texas Board of Health to adopt rules cov- ering construction standards for on-site sewerage facllltles. §301.17. Genera! Procedures and Infor- mation. (a)' Purpox. It is the policy of the Texas Deparunent of Health that individual on-site sewerage facilities shall be designed, constructed, and operated [o provide ade- quaze sewage treatment and deposal that will not contaminate potable water supplies or threatrn the health and welfaze of the public. Therefore, [he primary purpox of thex standazds is [o establish miniarauy-ac- ceptable standazds for constructing on-site xwerage facilities. These construction stan- dazds will cover the aspects of on-site sew- erage sysutns for use by individual homes, small business establishmeats, recreational aeeas, institutions, and other activities that conform [o this section and do not have ac- cess to a central collection sysum. The various types of treatment processes covered by thexstandazds do not have any open dis-' charges [o [he surface of the ground. Any process which proposes open discharge should be designed in accordance with 31 Texas Administrative Code, Chapter 317 (relating to Design Criteria for Sewerage Systems) and must be operated under a waste dixharge permit issued by the Texas Wauz Commission. For daily flows over 5,000 gallons per day that are proposed for sub- surface disposal, the determination of the necessity for a wane dixhazge pertnit must be obtained from the Texas Water Commig- sion. (b) Defuritions. The following words and terms, when used m thex sections, shall have the following meanings, unless the con- text clearly indicates o[herwix. (1) Aerobic digestion-The bacteri- al decomposition and stabil'vation of sewage in the prexnce of free oxygen. (2) Anaerobic digestion-The bac- terial decomposition and stabil'vation of xwage in the abxnce of free oxygen. (3) Bedrock-A continuous hori- zontal layer of hardened mineral deposits that does not support gowth of common plant life. (t'~ pisc~:,vz+er-All ~ewage other to be treated prior [o disposal to the earth's subsurface. (5) Bore hole-A drilled hole four feet or greater in depth and one to three fat in diameter. ' (~ Caliche-A white or pale yellow deposit of isrbonau and/or sulfates of vary- ing hazdness that exists in the soil profile. (7) Cesspool-A non-watertight covered receptacle intended for the receipt and partial treatment of domestic sewage. This device is constructed such that its sidewalls and bottom are open jointed to allow the gradual discharge of liquids while retaining the sohds for anaerobic decomposi- tion (See §301.16 of this title (relating to Un- satisfactory On-Site Disposal Systems)). (g) Chemical-A liquid or pow- dered waste that in sufficirnt quantity could have a biotoxic effect on on-site sewerage facilities. (9) Chemical toilet-A portable toi- let using chemjcals to mask odors,. dis- courage mutt breeding, and provide partial disinfection. (]0) Collective system-An on-site xwage collection, treatmrnt, and disposal system designed to serve two or more sew- age-generating units where the total com- bined flow from all units does not exceed 5,000 gallons per day. (I1) Commission-Texas Water Commission. (12) Composting toilet-A disposal facility designed to decompox non-wazer- borne hurnan wastes through bacterial ac- tion fanlitated by aeration. (13) Department-Texas Depart- meet of Health. (14) Evapotranspiraflon system- Asubsurface xwage disposal system which relies on soil capilarity and plant uptake to dispox of treated effluent through surface evaporation and plant vanspiration. (1~ Figure-Anyteferrnceinthex sections to a Figure Number is. a refsrrnce to a figure shown in $301.17 of this title (relating to Tables and Figures). (1~ Gravel less drainfield pipe- A generically labeled large diameter (usual- ly eight or 10 inches) geotextile fabric- wrapped piping product which is intrnded for ux without gravel in a subsurface sewage disposal system. (17) Greywater-Wastewater from clothes washing machines, showers, bath- tubs, handwashing lavatories, and sinks that are not used for food preparation or disposal of chemical and biological ingredirnts. (IS) Holding tank-A watertight container used to receive and store sewage in an anaerobic env'vonntrnt pending its delivery to, and treatment at, an approved treatment facility. This type of facility is generally rounded for interim use, if and when approved by the local permitting authority. (!9) Individual-A person, group - _....._.. ._ ,,,-+:,.~ nr'n? ~' x-'Witted .o ~.rvr, ar ~.:__-e:.i estate. 5 (20) injection well-A hole drilled into permeable soil which is intended to receive either raw xwage or the effluent from some form of treatment process. See §301.16 of this title (relating to Unsatisfac• tory On-Site Disposal Systems). (21) ~nnova[ive design-Detailed drawings and specifications describing the construction of on-siu xwerage facilities that utilize materials aqd concepts not in- cluded in thex standards. (22) Mobile home park-Any faci- lity or area developed for lease or rental of space for the placement of two or more mobile homes. (23) Mound system-A soil absorp- tionsystem which is installed in or below an artificially seated mound of earth. (24) Natural soil-Earthen materi- als deposited into place by natural processes and. not disturbed by artificial processes. (25) On-site aerobic treatment unit-A watertight covered receptacle de- signed to receive, store, and provide treat- ment to domestic xwage received through a building sewer. Its function is to xpazate solids from the liquid, promote the aerobic digestion of organic matter through the use of a forced air supply, store and aerobically digest settleable sohds, and allow the clarified liquid to be disposed of in a subsurface dis- posal system. (26) On-site xwerage facilities- Septic tanks, pit privies, cesspools, xwage holding tanks, injection wells used to dispox of sewage, chemical toilets, treatment tanks, and all other facilities, systems, and methods used for [he disposal of xwage other than the disposal systems operated under a per- mit issued by the Texas water Commission. (27) Pi[ privy-A vented water- proof vault intended to store human wastes and allow its decomposition through natural processes. In this type of treatment, no ex- ternal water source is provided and there is no direM discharge to the surface. It is recommended for'use only in primitive and remote areas. (Zin Platted-Recorded with the county in an official plat record. (29) Portable toilet-A small pdr- table rnclosure with a built-in toilet seat and a raw sewage holding tank. It is primarily intended for ux a[ construction sites and other areas where temporary restroom faei- 6ties are required. Domestic xwage collected in thex facilities is grnerally retained in an anaerobic state pending delivery to, and treatment at, an approved treatment facility. (30) Pressure dosing-The uu of some form of pumping device and a network of smog diameter piping to distnbute treated effluent within a subsurface xwage disposal area. (31) Sanitary control eaxment-A document securing all land, within 150 feet of a public or private potable water well loca- tion, from pollution hazards that include, but are sot limited to. solid and liquid waste disrrusal snu, arur.ai xns, imuropcriy ,.::riui or abandoned wells, major sewage pumping and treatment plants, and drainage ditches which contain industrial wazte discharges. (32) Scum-A mass of organic andlor inorganic matter which floats on the surface of sewage. (33) Seepage pit-An unlined cov- ered excavation in the Bound which is de- signed to oper'ete in essentia6y the same manner az a cesspool (See §301.16(c) of this title (relating to Common Unsatisfactory On- Site Disposal Systems)). (34) Septictank-A watertight cov- ered receptacle designed to receive, store, and provide vestment to domestic sewage re- ceived from a building sewer. Its function is to separate solids from the liquid, digest organic matter under anaerobic mnditons, store the digested solids through a period of detention,. and allow [he clarified liquid to be disposed of in a subsurface deposal system. (35) Sewage-Water which con- tains, or which has-been in contact with, organic and inorganic contaminants such az human or animal wastes, vegetable matter, cooking fats and greases, laundry and dish- washing detergetus, and other chemical com- pounds and wazte products. (36) Single family dwelling-A habitable svusure constrused on, or brought to its site, and occupied by one or more persons. (37) Sludge-A semi-liquid mau of partially decomposed organic and inorganic matter which settles at or near the bottom of a receptacle containing sewage. (38) Soil-The unconsolidated mineral material on the surface of the earth that serves as a natural medium for the growth of plants. (39) Sail absorption system-A- subsurfacesewage disposal system which re- lies on the soil's ability to absorb moisture and allow its dupssal by lateral and vertical movement through and between individual soil particles. (40) Split system-A wastewater disposal system that vests and disposes of blackwater and greywater separately. (41) Subsurface sewage disposal system-A network of perforated piping in- stalled below ground level which is used to distribute pretreated sewage effluent over a given disposal area. (42) Table-Any referrnce in these sections to a Table Number is a reference to a table shown in §301.11 of this title {relating to Figwes and Tables). (43) Ultra low-flow toilets-Toilets that ux 1 %x gallons or less per Plush. (c) General envuonmental require- ments. (1) Background. These wnslrusion standards are bring adopted under authori- ty of the Texas Sanitation and Health Pro- tection Law, T=xas Civil Statutes, Article q,%%-!. The vn-site se~.vage disposal sysrnm de.^.cc::. For thn pU'froSL, !Ire properly in- stalled septic tank performed well and permitted the remote rural residrnt to utilize the convenience of indoor pitwbing. Dur- N8the Past 30 Years, the population distn'bu- tion in the United States has shifted from rural to urban, thus seating rapid develop- ment in and on [he fringes of urban areas. Many residential subdivisions have been (opted beyond the limits of organized water and sewerage facilities causing the raidrnts to rely on individual resources available within the boundaries of small lots or vacts of land. On-site sewerage systems have been used frequently az the mearo of liquid wazte d'uposal. Unfortunately, in many rases, sub- divisions were located in areas with soil con- ditions unsuitable for conventional systems. Quite often, tot sizes are no larger than those found in subdivisions serviced by antral water and sewerage systems. Residrn[ial areas with small lots served by individual systems, on many occasions, are subject to undesvabie conditions such as widespread saturation of the soil, malfunction of [he treatmrnt unit, sewage on the surface of the ground and in roadside ditches, and svained relatiopships between neighbors. The stan- dards presented huein arc based on the cumulative observations and experiences of the past and are intended to provide the citizens of [his state with adegtmtepublic health protection and~a-minimum of rnvi- roamrntal pollution. (2) Fadlity owtters responsibilities. A properly designed onsiteEewerage facili- ty. Properly constructed in a suitabk: soil. can malfunction if the amount of water it is re- quired to dispox of ianotconvolled. [twill be the responsibility of rite owner to main- tain and operate the facility in a satisfactory manner. The proper performance of an on- site sewerage facility cannot be guaranteed even though all provisions of these standards have been met. Inspection and licensing of an on-site sewerage Facility by the licensing authority shall indicate only~that the facili- ty meets minimum requirements and does not relieve the owner of the property from complying with county, state, and federal regulations. On-site sewerage facilities, although approved as melting minimum standards, must be upgraded by the owner, at the owner's expense, if the awns': opera- tion of the facility results in objectionable odors, if unsanitary conditions are seated, if pollution or nuisance cotulitions are threaz- rned or occur, or if the facility when used does not comply with governmental regula- tions. (3) Locational and environmental standards. The developers of subdivisiots or mobile home parks that are remote from organized sewage cohesion systems shall consider the method of sewage disposal in the determinatiori of lo[ size and arrange- ment. T'he provision of a cohesion system and central treatment plant is grnerally the preferred method of sewage disposal. ~c~.eer, 'f -oil cenditiers permit, and othc factors are favorable to the use of on-site /~ adr. nted Rules C sewerage systems, the standards in Table I shall be used with regard to the location of the systems' components. A sewage disposal plan shad be submitted to the appropriate local regulatory authority a minimum of 45 days prior to anticipated date of construc- tion. (d) Authority of the departmrnt to regulate on-site sewerage facilities. The Texaz Sanitation and Health Protection Law, Texas Civil Statutes, Article 4477-1, covers the department's authority to promulgate wnstrusian rules and standards. The Texas Water Code, Texas Civil Statutes, §26.031, directs the commission to consult with the commissioner of health for recommenda- tions concerning the impact of the rue of on- site sewerage systems an public health before rntering an order regulating the installation or use of such facilities in a given area. (e) Relations with other governmen- tal rntities. (1) Texas Water Commission. The state level responsibility for the managnnrnt and mnvot of on-site sewerage system prac- tices is shared by the commission and the department. The mmmission's authority is primarily of a regional nature insofar az the control of po8ution caused by on-site sewerage systems. When the problems of a particular area arc likely to produce hazards to public health through area-wide water po8ution caused by on-site sewerage systems, the Texas Water Code gives the authority to limit the number and type of these systems, prohibit the irutallation and use of additional ones, and provide for their gradual and systematic reduction in that area. (2) Texas Water Well Drillers Board. This state agency shares raportsibility with the departmrn0 and the commission`for [he regulation of water well siting and con- struction. If aprivate water well rnsoacha an an atready established on-site sewerage system, the sewerage system owner should wosult with the Texas Water Well Drillers Boazd in order to establish the fact of prior right to use the sewerage system. (3) Local health departmrnts. The Texas Sanitation and Health Protection Law, Texas Civil Statutes, Article 4477-1, rt gaires local health officials to abate nuisances, and to aid the State Board of Health in the noforcement of its rules, regulations, requirements and ordinances, and in the enforcement. of all sanitary laws within the jurisdiction of dte (oral health of- fidak. Local health agendes may be required by city ordinance or waste control order to enforce regulations which excced the re- quiiemrnts of these standards, but local authorities must not permit~their standards to fall below those recommrnded by the departmrnt. Local regulations shall be reasonable and, if technical in namre, must be based on sound engineering prinriples. (4) River authorities and water distriss. River authoritiesor water districts may assist in water pollution convof enforce- ment procedures through orders Issued by Inly ~10, /987 I? TezRe~ 21?I the comnsis9'on to control or prohibit the use of on-site sewerage systems in an azea. The ootomis.5ibn may delegate them as the licens- ing authority W devebp procedures concern- ing administration, inspection, issuance of licenses, and enforcement of ac"otnatission order. Through [hex procedures, river au- thorities and water districts may estabbsh standards higher than those of the depart- ment, provided they ere reasonable and, if technical in nature, are based on sound engineering principles. (5) County comddssioners courts. Texas Water Code, $26.032, empowers the commlssioner~ court of any county to adopt a waste convol order controting or pro- hibiting the installation or ux of on-site xwerage systems in any area of a county under its jurisdiction. Thecommission~mus[ grant its approval of the adopted county order prior to its becoming effective. The order includes construction standards pro- mulgated by counties which may be adjusted m local conditions so long as they do not fall below the standards of the department and ako provided that the adjustments are rea- sonabkand, if technical~in nature, are based on sound engineering principles. (6) Muni©pal corporations. Cities, towns, and villages may control or prohibit the ux of on-site xwerage systems by local ordinance. The standards xt forth in any such otdittance must not fall below thox stated in this publication, but thex entities may establish standards which will produce a higher quality of operation, provided the standards are reasonable and, if technical in nature, are based on sound engineering prin- ciples. ('7) Regional councils of govern- mrnt. Thex agencies aze prindpally seated to establish and execute the phumirtg process in a region designated by the governor under authority of Texas Civil Statutes, Article 1011m. The regional councils may contri- bute to the effective and proper disposal of xwage by guiding developers to the more favorable alternative of sewerage collection systems and centralized sewerage facilities, preparing soil maps showing favorable, in- termediate, and unacceptable locations for sewerage systems dependent upon subsurface effluent disposal, and assisting local governs menu in recognizirtg the need for regulatory devices for sewage disposal. (f) Design approvals of on-site xwerage systems. (1) Approval of conventional de- signs. The construction standards contained herein aze pcomulgdted under authority of the Texas Sanitation and Health Protection law, Texas Civ~7 Statutes, Article 4477-1. In addition, Article 4477-1 statc~ that disposal of human excreta in populous areas must be by methods approved by the departmrnt. It further stales the effluent from septic tanks (or aerobic treatment units) shall be disposed of thrauglt subsurface draintie'.ds designed in accordance with good public health ._ -._. .._.- -. _ ;f7 in this subsection constitute the minimum criteria estabhshed and approved by the department for methods of on-site xwage disposal. (2) Approval of imovative designs. Agencies vested with the resporwbjlity of en- forcing on-site xwage disposal regulations tray consider feasible innovative designs which are not specifically covered in these construction standards. Texas is a large state with many differrnt types of topographical, geological, and climatic conditions. New systems may be conceived in the future to meet requirements demanded by these con- ditions. The systems may differ from [he specific construction methods outlined m this publication. To both assist local regulatory agencies In determining the reliability of a new system and protecf[he public from im- properly designed systems, the department will review and evaluate new systems on an individual basis. A system found to be designed in azcordance with good engineer- ing practice will be approved by the i(cpert- ment for the one installation for which the design was intended. Subxquent similaz designs for other installations will be re- viewed by the local regulatory authority. All new and innovative ~ must be submit- ted through a local regulatory authority to the departtttent for review as a clearing hoax procedure. At the,.degartment sdiscretion, local regulatory authorities havutg quahfied technical expertix will be assigned authority to review each design and administer a pro- gram to evaluate the design's in-place per- formance. A 12-month trial operational period shall be reguved. prior to any final approval by the department of any innova- tive design. (A) Innovative systems. Submis- sions of innovative systems for review must include: f) _ .detailed plans sealed by a registered professioria7 m~~ or sighed by a registered professional samtan'aT (iiJ necessary iesearcli data to establish the validity of the process, including xtup of the ppreposed innovative system; (i7t) development of opera- tional data and maintenance instructions; and (ivJ all research and develop- mrntdatathat has been verified by published results of a recognized college, university, or research organization. (B) Expenses. All expenses in connection with research, pibt projeMS, and/or demonstration projects must be borne by the activity submitting the in- novative design for review. (3) Approval of proprietary sys- tems. All new systems which deviate sigti- fieandy from these construction standards shall be reviewed by the department for Ihev installation and use suitability. Notice of disapproval by either the department or the !eczi -equlatcry authorty shall prevent such 'x ~; Rr,isrer ~ ~7 facilities from being installed. Categorical approval of proprietary systems will no[ be granted by the department. (4) Residential lot sizing. (A) General considerations. The failure of an on-situ sewerage system maybe caused by a large number of circumstances, including inadequate soil percolation, im- proper construction, desigrt, installation, and misux. The single most important factor wnceming public health problems resulting from these failures is the residential dwell- ing density which is primarily a function of lot size. The failure of a system in a highly populated azea is the fundamental cause of public health hazards resulting from on-site sewage disposal. Surfacing sewage provides a medium for the transmission of disease and the fact that many people are in [he vicinity causes concern over the spreading of disease. Sewerage systems using soil absorption for effluent disposal are more likely to malfanc- tion in high population den;ity situations becaux dte soil available to absorb or evaporate the effluent is limited. The failure of an absorption system on a small lot can be flnanaally disastrous to [he owner betaux the lot may not contain sufficient room to construct a new absorption field in a new location. (B) Platted subdivisions served by a public water supply. Subdivisions of single family residrnces platted after Ianuary 1, 1988, and xrved by a public water sup- ply but utilizing individual subsurface methods for sewage disposal, shall provide for individual lots having surface areas of at least one-half acre, or shall have asite- specifle design by a registered professional engincer or registered professional sanitarian and approved by the department or its de- signs. In no instance, shall the area available for such system be less than two times the design area. The surface area must be free oC restrictions indicated in Table I and thox referred to throughout this publication. (C) Platted subdivisions served by individual water systems. In subdivisions platted after Ianuary 1, 1988, for single family residences where each lot maintains an individual water supply well and sewerage system with a subsurface soil system, the plat shall show the approved well location and a sanitary control eaxment around the well within a 150.toot radius in which no subsur- face xwerage system may be constructed. A watertight sewerage unit or lined evapovan- spiration bed with leak detection capability may be placed cloxr to the water well than 150 feet, provided the minimum separation stared in Table I is not violated. To l~lml~P the possibility of the transmission of water- borne diseases due to the pollution of the water supphed for domestic use, each lot in a platted subdivision shall contain not less area than one acre, or shall have asite- specific design by a registered professional engineer ~ or ~a registered professional sanitarian and approved by the department or its designee. [n no instance shall the area available for such systems be less than two times the design area. The surface area must be free of restrictions indicated in Table I and those referred to throughout this publi- cation. (D) Smaller Lots or Tracts. The construction or installation of an on-site sewage facility on a lot or tract thaz is smaller than the size required in §301.11(fx4xB) and (C) of [his section shall no[ be allowed. However, on such smaller lots or tracts, recorded with a county in its official plat record prior to January I, 1988, an onsite sewerage facility may be permitted to be con- structed and licensed to operate if it meets the following criteria. It must be demon- strated by a thorough investigation of a registered professional engineer ort'egjstered professional sanitaziart• (either having demonstrated expertise in on-site sewerage system design) that an on-site sewerage facili- ty on one of these lots can be operated without causing a threat or harm to an ex- isting or proposed water supply system or to the public health, or creating the threat of pollution or nuisance conditions. (5) Mobile home pazks and multi- use residrntial developments. Mobile home parks and multi-use residential developments which are owned or controlled by an indivi- dual and which rents or leases space, or mobile home pazks and multi-use residen- tial developments which are sold but owner- ship and control of a central water system and/or a central sewerage system is vested in a responsible rntity, may utilize smaller lots than stated in paragraph (4)(B) of this subsection, provided an overall sewerage plan is submitted to [he department or its designee and approved and water is supplied by a central water system. Pazks and devel- opments of this type may connect no more than 20 units to a single sewerage system,-- provided the system is designed by a iegis tered professional engineer or registered pro- fessional .sanitarian. The total anticipated sewage discharge shall not exceed 5,000 gallons per day from the connected homes and [he sewerage facility must conform to the definition of on-site sewerage facilities in subsection (bx21) of this section. In- dividual home sites must meet the requ'ue- ments in paragraph (4) of this subsection unless applicable under this section. (~ Exemptions and variances. Re- quests for exemptions or variances of any part or parts of these standards for the design, installation, or operation of any on- site sewerage system 5ha11 be considered on an individual basis. The burden of proof is the responsibility of the .teg_istered profes- sional engineer, registered professional sa- nitarian, or other qualified individual responsible for the design or installation of the system under consideration. This in- dividual must demonsVate to the satisfaction of the deparmett or licensing authority, that thz z;emction ~. r variance has been requested ment can be provided by alternate means or construction features. Any such toques[ must be accompanied by sufficirnt rngineering or applicable data to mcet the departmrnt's or licensing authority's satisfaction. The depart- ment shall, at the request of local authorities, provide evaluation and commrnt services for any such local authority. §30l.l2. Design Standards jor Sewerage Systems. (a) Septic tank design-residential. (t) House sewer. The sewer from the house pltumbing system to the septic tank shall be constructed of structurally sound pipe such as cast iron, ductile iron, or SDR 35 (or equivalent) plastic pipe with metallic locating tape, bedded in sand. Cast 'iron, duttile iron, Schedule 40 PVC, or high strength pipe should always be used under driveways. The pipe from the house to the septic tank shall have a minimum inside diameter of not less than three inches and be compatible with the house stub out pipe. The slope of the house sewer shall be no less than '/.-inch fall per foot of pipe. The stub out location shall be at the highest possible elevation with respect m the house founda- tion to avoid deep treatmrnt systems. The line must be of watertight construction. A cleanout plug must be provided within three feet of the building and at 90° turns in align- ment, both horizontal and vertical, and at every SO feet of straight horizontal piping. Prospective installers and users of low flush commodes should consult with the trumufac- turers of these devices regarding their grade requuemrnts. Too steep or too shallow slopes on pipes connecting the toilet and the treatment tank may require excessive main- tenance. Piping from the Veatmrnt tankage to the disposal area must have at least two inches inside diameter, have at {east a minimum fall of I/8-inch per foot and be as sturdy as SDR 35 PVC piping. Metallic locating tape shall be used with the installa- tion of all piping to and within the disposal area. This tape shall be readily detectable with a metal detector. (2) Septic tank capacity based on sewage loading. A properly designed septic tank shall be watertight. The settleable and susprnded solids will undergo partial decom- position under anaerobic conditions. As a result of use, the septic tank will accumulate partially decomposed solids which must be removed periodically. As additional sewage is introduced into the tank, partiaIly clarified effluent is discharged into the subsurface disposal field. The best method for estimat- ing the tank's sewage loading is based upon the number of bedrooms in the house. Table II shall be used to determine the required minimum septic tank liquid capacity. (3) Inlet and outlet devices. To assure rapid drainage of house plumbing, the flow line of the inlet pipe shall be at least three inches higher than the operating tank liquid level which is determined by the flow lire of the outlet pipe. Liquid penetration of the inset :;ev~cz =_hai: be at :east six inches, ~' ~ Adopted Rules but never greater than that of the outlet device. Liquid prnetration of the outlet device shall be approximately one-fourth to one-half of [he tank's liquid depth. T branches are required for inlet and outlet devices because they provide a means for vrnting the gases produced by the decom- positioaprocess from [he tank and absorp- tion system through the house plumbing. Otherwise, gases may escape from around the lid of the tank and cause an odor nuisance in the vicinity of the septic tank. ' T branches also offer ready access for re- quired maintenance. To prevent the escape of floating solids from the tank to the sub- surface disposal field and the possibility of inlet stoppages, the open spaces between the tops of the inlet and outlet devices and the underside of [he tank cover shall not be greater than four inches, nor less than two inches (Sce Figure 1). In order to provide a good watertight septic tank, the itiltt and outlet T branches shall be installed in a per- manent manner at the time the septic tank is constructed. Factory built tanks shall have the T branches grouted in place before deli- very so that the only connections to the tank at the point of installation will be the influrnt and effluent lines. Manufacturers of prefab- ricated tanks shall be allowed to install watertight flanges into the tank walls, into which inlet and outlet stubs can be easily fit- ted by field installers, causing watertight con- nections. (4) Details of septic tank design. (A) Two single compartment tanks in a series, or a two compartment tank, with approximately one-half [o two- thirds of the total volume in the lust com- partmrnt, will be required for acceptable solids removal. Tanks may be round, rec- tangular, or o[ a shape [hat allows the de- partmrnt's standazds to be met. The second tank or compartment shall have inlet and outlet devices designed the same as for a single-compartment tank, except that the elevation, or flow line, of the inlet device in the second unit shall be the same as the outlet device in the first unit (See Figure 2). A 10.inch minimum diameter or square port shall be provided [o each flow line device for inspection, cleaning, and maintenance. Both the inlet and outlet devices shall be ac- cessible for inspection and maintenance without having to enter the septic tank. For tanks not having more than I2 inches of earthen cover, the use of sectional stab covers will conveniently and safely provide [he needed access. For tanks buried more than 12 incites, manholes with risers are re- quired. The septic tank shall be of sturdy, watertight construction. Materials used may be steel-reinforced poured-in-place con- crete, stcel-reinforced pre-cast concrete, reinforced fiberglass, polyethylene, or other materials approved by the regulatory authority. Metal septic tanks are prohibited because they are subject to corrosion. The septic tank shall'oe structurally designed to rest bucsiiny from steracl h;~c: au!s lalo /0, /9R7 /_' TexReg 22J3 loading and exterior loading caused by earth fill, garden tractors, riding lawn mowers, or any expected maximum wheel weights. At the oprion of the regulatory authority, the tanks shall lSe tested by filling with fresh or construction grade water followirig in- stallation and checked 24 hours later for leaks and structural integrity. Tanks ex- hibiting obvious deflections, leaks, or defects that will impair treatment must not be used. Where concrete tanks aze installed, sweating, or condensation at construction joinu is acceptable. (B) Tn the case ofpoured-in-place concrete tanks, septic tank bottoms shall be at least six inches thick with 6x6x6 gauge welded steel mesh or number three reinfor- cingbars on six-inch centers, with such refrt- forcing materials being extrnded up into the wall azea of the tank so that it will mesh with the reinforc'vrg materials in the walls of the tank. The floor and walls must be con- structed monolithically. Walls are to be a minimum of six inches thick. (C) Septic tank tops reinforced with 6x6x6 gauge wedded steel mesh or number three >ginforeing bazs on sin-inch centers must be poured off-site rather than on the tank (not on top of a wooden frame. over the tank) and must be moved onto the tank after hardening and then sealed to the tank with a permanent bonding material or rubber gasket having cone-half inch mini- mum thickness so az to form a seal between tank and top. To facilitate handling, tops may be poured fn sections but must be sealed when in place. Tops must be a minimum of three inches thick. ' (D) Pre-cast concrete, polyethy- lene, and prefabricated fiberglass tanks ~aze subject to prior approval of the licensing authority, who should consult with the de- partment regarding the uniquely differing maretials, manufacturing mMhods, and de- signs used. AG precast or prefabricated tanks shall be clearly mazked, tagged, or stamped with the manufacturer's name, an exclusive serial number,"and the capacity of such tanks near the level of the outlet in at least two positions so as to be clearly visible to the ittspecting or pemiltting authority even after they have been placed in the ground.. Listing of [his information with"the address of the installation shat be maintained by the regulatory authority. (E) Septic tanks must be installed so az to provide at least 12 inches drop in elevation from the bottom of the outlet pipe to the bottom of the disposal area. A sand pad, sandy loam, or select material with a minimum thickness of four inches must be placed under all prefabricated tanks. All sep- tic tank excavations must be backfilled with sand, pea gravel, select backfill, or loam not containing rocks greater than one inch in size. It is acceptable to mound sandy loam oJer a septic tank which is set high to main- tain fall to the drainfie!d. (F) When !carted sewage must be pumc~^_ .c ,~ e a:..-;: c.' ....... an tf:'.cent 12 Tex Reg :234 Jult• l0, 198i pump shall be placed in a watertight tank. A check valve shall be provided if the disposal area is upgrade and higher than the pump. The tank shall be provided with"a highwater alarm having a power circuit 'separate from the pump. The electrical con- nections shall behard-wired, external to the pump chamber. Effluent pump tanks 5ha11 have a minimum capacity of 500 gallons after the alarm is activated. (b) Septic tank design-institutional. (1) General consideration of use of septic tank systems. Septic tanks may be used az a means of sewage treatment for non- residrntial activities. Hqwever, experirnce in- dicates that the usefulness of the septic tank systems decreases az the size of the establish- ment served increases. Whence septic tank fs being considered for service to an activity that will produce more sewage than a single family residence, design guidance must be obtained from a local health department, regulatory agency, or a consultant who is professionally registered as an engineer or sanitarian in Texas and is well versed in on- site sewerage system design. (2) Sewage loading. The total quan- tity of sewage applied per day to the septic tank provides the basis for the determina- tion of its size. Table III will be of assistance N estimating the daily sewage flow per capita for a variety of living and activity situations. Organic loading of sewage from restaurants, hospitals, nursing homes, and other com- mercial establishments will require an in- crease in tank size. (3) Compartments to be provided. Two compartments shall be provided, the tics[ created by a wall with a tee to permit liquid flow from the firs[ compartment [o the second one. The flow Gne of [his inter- mediate fitting shall be at the elevation of the flow Gne of the outlet fitting of the se- cond compartment. The fitting shall be three inches below the elevation of the flow line of the first compartment's inlet fitting. The capacity of the first compartment shall be one to two times [he capacity of the second compartment. All tanks must be vented in- ternally. (4) Selection of septic tank capaci- ty. The net volume or effeMive capacity below the flow Gne of a septic tank for flows up to 250 gallons per day shall be at feast 750 gallons. For Flows between 250 and 5,000 gallons per day, the capacity of the tank shall be equal to at least three days' sewage flow, For daily Flows over 5,000 gallons per day, the determination of the necessity for a waste discharge permit must be obtained from the commission. (S) Pump tank usage. When treated sewage must be pumped to the disposal area, an effluent pump shall be placed in a water- tight tank. A check valve shall be provided if the disposal area is upgrade and higher than the pump. The tank shall be provides with a highwater alarm havi::g a pewe: cis - cuit separate frem the p~.:m-p T'ne o!°•:!ricd Tex:zs Register - . 9 the pump chamber. Effluent pump tanks shall have a minimum capacity of 1,000 gal- lons after the alarm is activated. For daily Flows over 500 gallons, a duplex pump con- figuration must be provided. ,,. ' (c) On-site aerobic sewerage plants. (1)- Introduction. A number of small (up to 1,500 gallons per day) aerobic waztewater disposal systems have been designed and marketed for the on-site Vea[- ment of sewage. The information in this subsection relates to the department's re- quirements concerning the installation and use of on-site sewerage plants for private residences, small businesses, and institutions. Sewerage plants designed to treat more than 1,500 gallons per day must mcet the design criteria for sewerage systems, published by the. department and the commission. (2) Appropriate usage. The installa- tion and use of individual wastewater dis- posa~ units, other than septic systems, are acceptable to [he department provided they meet department requirements. (3) Permit policy. Subject to the re- quirements of the local regulatory authori- ty, anowner of a home, small business, or institution may elect to use an aerobic in- dividual wastewater disposal system. (4) Effluent disposal practice. The effluent from an individual small aerobic wastewater disposal unit must be discharged into a properly designed and constructed subsurface sewerage system. No discharges to or above the ground surface or into the waters of the state are authorized by the department. Such practices may be permit-_ led by the commission and [he department 1 on a !'united Dazis through the implementa- tion of local regulatory programs. (5) Operation and maintenance re- sponsibility. Companies distributing aerobic individual small waste disposal systems shall provide an inspection and repair service since the system's owners, in most instances, will not be in a position to judge whether the device is working az designed. Local govern- ments, in determining whether to approve any type of individual small wastewater disposal system, shall give consideration to the ability of the distributor or other firms qualified to service the installation. The pro- spective owner shall be givrn a copy of the prospective seller's service contract prior to making a decision regarding purchase. The contract shat be for a two-yeaz period, with provision for extending the period, at the owner's option. .(~ Emergency operarion. The prin- cipal structure or containing vessel of an in- dividual small wastewater unit is designed to provide treatment to a predetermined amount of daily incoming sewage. In the event of more than one day's failure of mechanical or electrical devices, anaerobic conditions will prevail when aeration equip- ment is inoperable. The unit's owner shall be prepared for emergencies by contractual arran 3emrnt with the plant's seller, by stock- pumping and hauling company, or by pre- venting the grneration of more sewage until the emergency is eliminazed. (n National Sanitation Fotmdation criteria. There are numerous manufacturers of individual small wastewater treatment systems. To the extrnt of available informa- tion, inquiries on individual systems from local governments or individuals will be answered by the department. Local govetn- mrnts interested in authorizing individual small aerobic wastewater disposal systems are advised of the [esdng and approval cri- teria ofthe National Sanitation Foundation (NSF). The NSF seal on a particular unit in- dicates iu ability to meet the requirements of the foundation's Standard 40, relating [o individual aerobic wastewater Vestment plants. Units not having a NSF approved rating wt11 be required to undergo extensive testing oqual to or greats than the faurida- tion's. program prior to use in Texas. The departmrnt will maintain a list of approved aerobic systems. (g) Treatment limitations. In addi- tion to the previously mentioned statement, the prospective user should be aware that small aerobic treatment plants treat sewage differently than septic tanks. Aerobic treat- ment plants operate by mixing raw sewage together with au and massy of bacteria. Several kinds of bacraia consume the sewage and au, dtanging it to nitrogen, carbon diox- ide, and water, all of which are used by plant fife. Treated clear effluent still contains microscopic bacteria and viruses that were in the raw sewage so it must be kept out of contact with the general public as much as possible. It is possible to disinfect treazed xwage with chlorine, bromine, ultraviolet light, ozone, or other commercially available products. However, nothing wtll make aero- - bically treated xwage safe enough to ux as fresh water. Disposal systems for aerobic plant efflurnt shall be the same as for septic tank effurnts. (9) Costs. Because aerobic treat- ment plants use a completely different pro- cess than septic tanks, there should be little or no odor if the plant k operated and main- tained properly. Operation and maintrnance rnsts are considerably greaterthan for xp- tic tanks, however. Most aerobic treatment plant suppliers will potion the homeowners about excessively loading the unit with gaz- bage dkposal waste or toxic materials. (10) Siting considerations- Most aerobic treatment plants sized for single home or small commercial shop use are usually only slightly larger than a septic tank but may not be installed as deeply. The organic loading of commercial or institu- tional appliptions may require individual design considerations. Its inspection access fs exposed to the surface, unlike a scpdc tank which is usually covered over with a layer of gravel or grass sod. The unit is generally one piece eerstruc:icn usinx corcre;e or (1I) Solids accumulations. Most aerobic treatment plants operate-by apply- ing a'u from an air compressor into the bot- tom of the tank that fast aaxpts raw sewage. As the air bubbles rix to the surface the sewage mixes with a mass of brownish gray bacteria called activated sludge. Several baf- fles and/or compartments arc requital with- in the single unit so that several different activities tact be done az the same time. These include tnudng the air, sewage, and bacteria together, then allowing the bacteria tb set- tle whTe the treated effluent k drained ofC the top. Solid materials that the bacteria pn- no[ consume will accumulate in a sludge holding compartment along with geese, oil, and other undigested Floating wastes. The sludge and floating wastes will have to be removed occasionally by a sludge hauling company. How often sludge has to be removed depends upon the type and amount of waste the owner applies to the system. (d) Greax traps. (1) Installation. Crease traps shall be used on kitchen wastetines from institu- tions, hotels, restaurants, srhook with lunch- rooms, and other places that may discharge large amounts of greasy and oils to the sewer. However, wastes from garbage grind- ers must not be allowed to enter a grease trap. Tht trap shall be installed near the plumbing fixture that discharge greasy waztewater and should be easily accessible for cleaning. When maximum efficiency grease removal is necessary, a dual eham- bered vap that xpazates, they stores grease shall be utilized. If the dual chamber trap is installed as clox as possible to the source of hot greasy waste, the separated grease can be conveyed to the secondary chamber, where it aceumulates, cook, and soGdifles. (2) Sizing. Grease trap sizing will depend on the particulars of the application. Building code authorities and trap manufac- turers should be consulted prior to sizing the unit. No trap with a liquid holding capacity of Ins than 100 gallons shall be approved for any food preparatory establishment re- quired to have a unit. Grease interceptors shalt be sized using the Uniform Plumbing Codt to determine maximum flow rate and requred [o have at ]ease two compartments. The primary compartment shall hold xven lima the maximum gallons-per-minute flow rate and the secondary shall hold five times this flow rate. If garbage disposals are re- qu-ved by the permitting authority, they shall be plumbed into the unit and the unit sized to hold IO lima the maximum gallons-per- minute Bow rate in the primary compart- ment and xven time this flow rate in the secondary compartment. §301.13. Design Standards jot Ejjluent Disposal Systems. (a) Soil technology ar,d disposal method se'.ecrion. Pr;cr ?o pre; eci bui!aing corstr„c•;oa. ? -... ,~.-_ -.. soil ;`_-aa- !17 sitiotung must be done. Site evaluation is a combination of field inspection, laboratory testing, and desk top analysis. [t includes a thorough understanding of the coda and re- gulations governing the ux of the site. Key elements of the evaluation are discussed in the foltowing pazagraphs. (1) Topography. A site's topogra- phy relates to the change in surface height over the site's total area. Topography can influence the choice of system used. For in- stance, pressure dosing may be the only type of system possible where the only acceptable location for the disposal area is at a higher elevation than the treatment unit. Grading plans to alter the topography may be used in order to evaluate whether the site can be used. Care must be taken to protect or re- place the site's topsoil. (2) Soil chazacteristia. The most important chaaacteristics of soil are the abili- ty to absorb fluid, provide adequate treat- ment, and convey the treated water under ground. Permeability k the characteristic relating to eax of water movement through soil. The main properties indicative of ab- sorption capacity are soil texture, (see Chart I) structure, color, thickness of permeable strata, and swelling characteristics. (A) Soil properties. Soli proper- ties aze discussed in detail by the United States Department of Agriculture, Soil Con- servation Service (USDA-SCS), in the soil survey reports which are available from county extension agents and field offices of the USDA-SCS in each county. Thex surveys include general soil maps which outline the areas of differrnt soils onto aerial photos. General information is given regar- ding the soil's suitability for xwage effluent disposal on a broad scale and can be used for preliminary evaluation. (B) Field investigazion. A careful field investigation must be made by persons trained or having qualified experirnce in soSs science or on-site sewage disposal to deter- mine the capability of a situ to absorb and treat wastewater, The investigation should be done dtuing the wettest season of the site. The soil evaluation should address the eight site characteristic listed in Table V. A site plan must be submitted to the local regula- tory authority showing the proposed lop- tion of the various componrnu of the on-site sewerage system and the existing or future improvements, lot ling and any other item that restritts the choice of component loptions. (3) Groundwater. Seasonal high groundwater (perched water) tables can ex- ist in any area of the state. Under such con- ditions, it k possible to locate perched water near the ground surface during wet periods each year. This situation k the result of seasonal rain storm runoff permeating into , a shallow soli mantle that lies upon an im- pecmeable material like a solid rock or very des<_t clay. The mechanism :for the mmovi o` ~hs water is by very slow drairirg to open. rock. Some moisture is taken up by evapora- tion and transpiration of plants that aze rooted into the permeable top sod. (4) Flooding. Usual site develop- mrnt requires that [he structure be built on the highest portion of the site. The sewerage system is developed in the remaining azea of the site that is lower than the structnre. Uh- fortuna[ely, the lower area of a site may be subject [o Flooding as it naturally receives storm runoff from all areas upstream of it. Careful evaluation of Flooding potential is necessary to determine whether Flood pre- ventative measures must be inwrporated into the on-site sewerage system. All of a soil ab- sorption system must be constructed out of the flood-prone area, and not within areas subject to inundation or erosion by Flood waters or rainfall runoff. An applicant for a permit to install a sewerage system shall wnsutt with the local flood plain ordinance administrator, county engineer, State High- ways and Public Transportation Depart- ment, nearest river authority, Farmers Home Adrtilnistration, Federal Emergrncy Man- agement Agency, and other officials who may have information regazding the potrn- tial for flooding at the disposal site. (5) Solid and fractured rock. Solid or fractured rock underlying a thin absorp- tive so0 mantle which is less than four feet thick poses two differrnt problems to the on- site sewerage system user. Solid material will reduce the absorptive capacty of a site while fractured rock may act as the mechanism for d'vect pollution of an aquifer [hat lies under the site. Percolation tests in these materials are uareliabie and must not be used to ails the sewerage system. • ~ (~ Caliche. Deposits of awhite-to- pale yellow mineral form of calcium car- bonate and related compounds of variable thickness and hardness that should be care- fully inspected by a soils scientist or qualified local authority to determine site suitability for treated sewage absorption. Caliche has several forms that may or may not allow the site to be developed as a sewage absorption area. However, if a soils scientist or qualified local authority is unavailable, an evapotran- spiration system can be installed if climatic conditions are appropriate. (~ Offseu from property lines. Minimum spacings from adjacent property owners must be adhered to. A common pro- petty line may be built upon with fencing or masonry walls. The area may serve as na- tural or artificial drainage for storm runoff. For these reasons, private on-site sewerage systems must not be built on these spacings, unless there is a written agreement be[wem the adjacent property owners involved. (8) Cleazances from structures and surface improvements. Table I indicates clearance requirements relating to structures aid surface 'vnprovemrnts. Structure foun- dations or surface improvements, such as e ~i ~ ming pools, conare curbs, landscap- ,- -r: s!k:ers~ tanare, asphalt, wood "~--~,.. .__. Tut.. r0, fS%.,7 be placed or planned for installation in any manner that will jeopardize the suitability of subsurface sewage disposal sites, unless a study by sC[egistered professional engineer or a'registered professional sanitan`ans ap- proved by the local permitting autbority. (9) Spacing with other utilities. Utility companies may have special restric- tions that can be rnforced onto on-site sewerage system installations. Safety of operations has been cited as a reason to maintain distance from buried electric and gas conduits. Safety to public health requires the sepazation of potable water piping from sanitary sewerage systems. Table I lists com- monly used criteria, but each utility company serving the pazcel should be consulted prior to installing the sewerage rystem even if no potential problems are evident. (10) Disposal system selection. In designing a private sewerage facility, several options concerning subsurface disposal are available. Table IV has bern prepared to aid in the selection of the proper system based on site evaluation, percolation rate, and lot size considerations. The table includes the systems generally recommended for subsuo- face disposal which are drainfields, absorp- tion beds, and evapotranspiration beds. The purpose of Table IV is to give the reader a general idea as to the most feasible type of system to construct taking into consideration lot siu, soil absorptive capacity, water con- servation practices, and local climate. (A) System Selection. After de- termining the siting of appropriate tteatmrnt tankage, the permitting agency shall confer with the applicant regarding the calculations to determine the bottom azea requved for trenches, an absorption bed rystem, and an evapotransp'nation system. Grnerally, the system having the least number of square -- feet of bottom area will be the most eco- nomical. In most cases where adequate room is available, a trrnch system will be less costly. (B) Low soil permeability. In areas where soils have low permeability, it is possible to desigt a system which combines both sod absorption and evapotranspiration. Such systems are somewhat complicated and should be designed by a person trained in sewerage system design. The United States Environmrntal Protection Agency has issued a publication en[ided Design Manual-0n- Site Wastewater Treatment and Disposal Systems that provides guidance to those in- terested in selecting [he most appropriate treated sewage effluent disposal method, tak- ing site constraints into wnsideration. The solve manual, EPA Publication Number 625/1-80-012, may be ordered from the U.S. Environmental Protection Agency, Office of Research and Development, Municipal En- vironmental Research Laboratory, Cincin- nati, Ohio 45268. This governmrnt publics lion is a 391 page document that was pub- lished in Ottober, 1980, for public use. Texas Regst9r ~ (~ ral references, the department does not adopt this manual or any other technical publica- tion. (b) Percolation test procedures. It has been previously mentioned that the percola- tion tat is but one of many indicators of a site's future suitability to accept sewage for safe permanrnt disposal. Consequently, it should not be considered as the sole basis of designing an on-site sewerage system. Ex- periences of local regulatory agents will have priority over the test results. Ex- perienceshould bebased on tests conducted during the wettest season of the yeaz. (p Location and number of tats. A minimum of two test holes wil(be requved with the holes uniformly spaced over the proposed absorption field site. The actual number of holes required for an individual soil evaluation should be determined expe- rimrntally in accordance with the following procediues. (A) Percolation rate resulu. If the percolation rate results of both test holes fall in the same group as shown in column one in Table VI, no additional holes will be necessary and the absorption field may be designed on the average of the results. (B) Adjacent groups. If the per- colation rate results fall in adjacent groups, the absorption field may be designed ruing the test results from the hole with the slowest percolation rate or one additional hole may be dug, tested, and all three results averaged. To properly average [he results, each test result must be converted to minutes/inch, then added together. The sum is then divided by the number of tests. If tesu ¢t an area vary by more than 20 minutes/inch, varia- tions in soil type are indicated and percola- tion rates should not be averaged. (C) Non-adjacent groups. If [he percolation rate results fall in nonadjacent groups, the absorption field may be designed using the test results from the hole with the lowest percolation rate or two additional holes may be dug, tested, and the results averaged. (D) Alternative procedure. [n lieu of the previously mentioned procedure, four holes may be dug and tested and the results averaged at the same time to reduce the amount of timt required to conduct the test. (Z) Type of test hole. Dig or bore a hole with a diameter of from six to t2 in- ches with vertical sides to the depth of the proposed absorption trench. The bottom of the hole must be at the same elevation as the proposed drainfield bottom. It maybe re- quved on a case-by-case basis by the local regulatory authority, that test pits with a back hce or other heavy excavating equip- ment bedone prior to performing the test from a bored hole in the bottom of the test pit. The local regulatory authority may re quire borings to a depth greater than the depth of the proposed disposal system bor tom, if a high groundwater table or impzr- me~ble 'aver is susrecled ro be oreses[. (3) Preparation.of tat holes. Care- fully snatch the bottom and sides of the hole ,with a knife blade or.sharp-pointed instr~- ment in order to remove any smeared soil surfaces and [o provide a natural soil inter- face into which water may percolate. Re- move all loose material from [he hole and carefully place approximately one inch of coarse sand or lure gravel into the bottom of the hole to protect the bottom from scouring. ' (4) Saturation and swelGrtg oC the soil. It is important to distinguish between saturation and swelling. Saturation means [har the void spaces betwern sod particles are full of water, This can be accomplished in a short period of time. Swelling is caused by intrusion of water into the individual soil particle. This is a slow process, especially in a clay-type soil, and is the reason for requir- htg a prolonged soaking period. (5) Filling of test holes. In the con- duct of the test, carefully fill the hole with clear water to a minimum depth of 12 in- ches. In most soils, it is necessary to refill the hole by supplying a surplus reservoir of water manually or by means of an automatic siphon, to keep water ht the hole until satura- tion occurs (approximately 24 hours). Dtter- mine the percolation rate 24 hours after water is fast added to the hole. This pro- cedure is to insure that the soil is given am- ple opporcurdty ro swell and w approach the condition it will fie in during the wettest season of the year. Thus, the test will give comparable results in the same soil, whether made in a dry or in a wet season.~in sandy soils containing,little or no clay, the swell- ing procedure is not essrntia( and the test may be made as described in paragraph ('%) of [his subsection after [he water from~one filling of the hole has completely seeped away. (6j Percolation rate measurement. With the ezcep[ion of sandy soils, percola- tion rate measurements shag be made on the day following the procedure described in paragraph (S) of this subsection. After the overnight swelling period, adjust the water depth to approximately 12 inches from the bottom, From a fued reference point, mea- sure the drop in water level over a 30.minute period. This drop is used to calculate the per- colation rate- If the rate is slower than 30 minutes per inch, continue with measuring the rate for an additional 30 minutes. The slower rate of~[he two consecutive one-half hour tesu should be used. (7) Percolation rate measurement (sandy soils). In sandy soils (or other soils in which the fast six inches of water saps away in less than 30 minutes, after the over- pight swelling period), the hole should be filled to a depth of six inches and that depth maintained by adding water for 30 minutes. After 30 minutes, the drop in water level should be measured over an additional IO- minute period and the percolation rate cal- culated from this measurement. (c) ECtluent disposal systems. (1) Generally. The efflurnt dis- chazge from a septic tank or aerobic plant requ'ves furcher handling to render it safe from a public health standpoint. Awell- designed subsurface soil absorption rystem will allow these liquids to seep into the ground without creating a health ttazazd or nuisance. After the prospective builder has selected a suitable azea and is asstued that safe distances from wells, lakes, etc. can be mairtained, the butgder must determine, with the~assistance of an experienced soils scien- tist, registered_yrot`esstonal~eer or r8- .gister~professiottal ~A~ ra~Ar,.whether soil formations in the selected area will allow a soil absorption system to work. When con- vrntional soil absorption rystetm are used, there shall be no interference from ground- water. The groundwater table must be situ- ated at least four feet below the bottom of the soil absorption system. In the coastal areas of Texas, fresh or salt water may oc- cur at depths less than four feet. The design • standards for conventional soil absorption systertrs set forth in this publication are based on the premise that impervious strata are at depths greater than four fat below the bot- tom of the absorption trench. Convntional soil absorption systems shall not be used if either 'unpervious strata or groundwater ex- ists at depths less than four feet from the trench or bed bottom, unless a detailed site evaluation is made and a design by a.te-gis- ~professiorta~engipeer pr rrgtstered pro- (essional sai'utarlan is accepted. by the local regulatory authority, (2) Soil absorption trench.~A soil absorption trench may be used if the pro- posed site provides sufficient room and is of suitable soil. An experienced soils scientist, registered professional engitteer, or tCpstced professional sanitarian should be consuRed to determine if the site qualifies for trrnches. (A) Absorption trench field for level terrain. Where the topography or ground slope is not too slap, a flat or level system of gravel-tilled trenches dr percola- tion beds is recommended. The trse of a looped trench system will avoid dead ends and assure maxhnum effective util'vation of alt portions of the system. No individual trench shall exceed 75 feet in length. (i) The fiekl6ottom must beat least t2 inches lower than the flowline of the treatment tank. The capacity of any parti- cular absorption system is determined by the total area oC trench or bed bottom built in- to the system. The amount of this required minimum area will depend upon the ezpeaed sewage load, the average soil percolation rate, and the site's soil evaluation results. The soil percolation rate may be determined by performing a perwlation test as described m subsection (b) of this section. The trench dimensions for single family residential units may then be estimated from Table VI. For sewage flows of less than 5,000 gallons per day from commercial or institutional estab- lishments, A, the absorption [reach boron requirrJ, is determined ~~~ the .`omv!a 4 = I ~.. ~ ,-unp[°c Ruins' 1.25 Q/Ra, where Ra, the allowable applica- tion race, is found in Table V I and Q is the daily flow. (fiJ Atl parts of the trench or bed bottom shag be at the same elevation. Trenches should be construMed as shallow as possible with a minimum depth of Ig in- ches and a maximum depth of 36 inches. Doper trenches should be used where snow [nay saturate the upper portion of the trench. For trrnclt depths greater than ?A inches (ex- cept whue snow exists), sand shall be used to fill the trench up to the top soil cover as shown in Figure 3. The trench width shalt not exceed 36 inches, as narrow trenches (12 to IS inches) are recommended. Although trench length is based on bottom area only, sidewall area is important since much of the wastewater is absorlxd through the sidewatls and is eventually evapotranspirated. Matd- mum allowable spacing between adjacent edges of parallel wenches is three trench widths. fill) Liquid from the sewerage unit is conducted to the absorption system via a watertight line similar to the house sewer. The liquid is distributed uniformly through the gravel-filled trenches by the use of three-inch to 10-inch perforated plastic pipe of any one size, or equivalent pipe ma- terials. It is important that the distribution piping be laid reasonably level (4 inches per I00 fat maximum allowable grade) in the Vrnchts, wi[It a minimum of six inches grav- el depth under the pipe, A total gravel depth of approximately IZ inches is required, The trrnch media must be clean graded gravel, brokrn vitrified brick, washed rock, crushed stone, or similar aggregate that tr generally one uniform siu (from 0.75 inches to 2.0 in- ches). tJyster shell, other types of shell, and soft limestone are not allowed for trench me- dia because the cementitious properties of this type of material often result in early trench failure. The distribution pipe shall consist of plastic perforated pipe, 4-inch cor- rugated polyethyirne, or equivalent materials with an SDR ratio (ratio of pipe diameter to wall thickness) not numerically greater than 41. Jointed rile is not recommended for use becaux of the difficulty in maintaining joint spacing and keeping the line level. Covering of several layers of newspapers, a layer of butcher paper, or geotextile filter fabric material over the top of the gravel is required to prevent the sandy loam or sand backfill from invading the gravel until the backfill becomes stabilized. When only san- dy loam is placed over gravel, only geotex- tile filter fabric shall be allowed. Taz paper or other impervious material shag not be used under any circumstance. The pipe se- lected for drainfield construnion shall have sufficient strrngth to resist crushing from es- temal loadings such as earth fill, gazden trac- tors, riding mowers, and similar yard equip men[. Bituminous fiberboard or paper pipe shall not be used anywhere in the sewerage system. Poor construction practices win curse serious damace to the sail ab~~upri~ ~r. - .U, ,- _ .... __ system. Prior to issuance of a permit, notice shall be givrn [o the regulatory authority of the types of piping proposed. (rvJ It is extremely important that care be takrn to avoid sealing the sur- face of the bottom and sides of the absorp- tion trenches though smearing. Trendxs or beds shall not be excavated when the soil is sufflcirntly wet so as to smear or compact easily. All.smeared or compacted surfaces occurring eluting constrncdon shall be raked to a depth of orre inch and loose material removed just before the gravel or other media is placed. The absorptive areas should not be walked on unnecessarily. The com- pleted surface of the disposal azea must not be paved, used for parking of vehicles, or covered with impermeable materials. (B) Absorption trench field for irregulaz terrain. Where the topography or ground slope is too steep for feasible-con- s[ruaion of aclosed-looped Vench system, the following alternate layout may be used. There shalt be a minimum lbinch drop from the bottom of the outlet pipe to the bottom of the Fust trench whrn trenches are installed in this wnfiguration. (i) A single Level trrnch, con- structed tike tlieclosed-looped trench, is built along a contour. The overflow from this trench is conducted via a watertight pipe to the next lower level where a second Vench can be built along a contour similar to the upper Vench. The pattern can be repeated until the required minimum vrnch bottom area has been provided. It is requved that no individual trrnc6 exceed 75 feet m Irngth. This technique is graphically ffiustra[ed in Figure 4. Other de[atls of trench construc- tion described in subparagraph (A) of this paragraph, and~shown in Figure 3, should be followed. The crossover trench must be as shallow as possible to prevrnt effluent from draining from upper to lower levels through disturbed soil. /ii) Table I should be reviewed if the irregular knain has sharp slopes and breaks. Consideration, of hydrogeological and ertgLteering data maybe txluircd by [he regulatory authority. (3) Soil absorption beds. In addi- tion to tbe trench-type absorption field, two or three absorption beds of reasonably equi- valent areas, separated by at least four feet and using watertight flow diversion valuing, (See Figure S), may be used in areas where the combination of soil percolation and lot siu precludes the use of a trench-type system with minimum spacing between trrnches. While absorption beds requve more bottom area than trenches, they tend to be mote compact. (A) Construction. The bed shall be constructed with its depth ranging from 24 inches to 36 inches. [[ shall be kept az shatiow as possible to promote aerobic bac- terial action in the soil. The botbm of the bed must be level to within plus or minus one inch for uniform wastewater distribu- tion. Fdl dirt, top soil, or other material unaoceptabk to the regulatory authority shall not be plaod on the bed bottom for any rea- son. Media (gravel, crushed stone, etc.) that is grnerally one uniform siu from 0.'75 to two inches shall be placed on the bed bot- tom followed ~by two or more distribution pipes spaced six to F2 felt apart and throe feet from the edge of the tied. The amount of gravel and spacing betwern the pipes is dependent on the siu of the pipe used. The dutribution pipe is thrn surrounded with ad- ditional gravel to the top of the pipe. The pipe must be one siu, from three to ]0 in- ches in diameter. The total depth ofthe gra- vel Nthe bed fs 12 inches. The grave! shall then be covered with fdtering materiel, such For Dwellings: A= 150 (1+B) as several layers of newspaper, a layer of but- cherpaper, or geotextile filter fabric, to pre- vent the final soil layer from invading the gravel and reducing porosity. The next soil layer shall consist of sand, sandy loam, or a mixture of the two. jB) Wicks. In order to provide continuous capillary action in the sand, wicks shall be incorporated in the rock media. Wicks are simply sand structures which penetrate through the rock media to the bottom of the bed (See Figure 5). The total wick area shall be ]0% to 15% of the bed surface area and shall be uniformly spaced throughout the bed. Wicks may also be constructed by simply grading furrows in the rock media in between the distribution pipe. In areas of the state~where rock media is difficult to obtain, [he total amount of rock media may be reduced by filling the in- itial 12 inches of the bed with coarse sand (2.0 mm) and placing rock ~tedict only around the top, bottom, and sides of [he distribution pipe to form an I8-inch en- closure. (C) Capillary medium. if clay, rock, or other semi-impervious material is excavated from the bed site, it must be re- moved and under no circumstances be used as backfill m the bed. Sand or sandy loam will provide a capillary medium to help eliminate some of the wastewater through evapotranspiration, as explained in paza- graph (3) of this subsection. The bed shall be filled to within six inches from the top with sand or sandy loam and mounded with sandy foam so that the center of the bed is approximately four inches above normal Bound elevation. This will provide drainage away from the absorption bed. When this system is used, the total absorption bed area must be calculated using the following for mules: Where: A =The total absorption lied area z~quired for two beds. B =The total number of bedrocans in the dwelling. Ra =-Sewage application rate for absorption trenches expressed as gallons per square foot of bed bottom, per day based on percolation rate. (See Table VI) For non-single family residential situations: A = 2Q Ra Where Q = The total daily vast=water discharge in gallons from that situation. _ .~:3aq "_.v .rua• 10. I4R% Ts~as3e;%stsr ''~ (') (4) EvapoVanspvation beds. (A) General. Evapotranspiration bed systems may be used m locations where soil conditions aze not suitable for any type of soil absorption system. For very porous soils, solutioned limestone, fractured bed- rock, and situations that would allow ex- cessively rapid migration of sewage toward groundwater, lined evapotranspiration beds must be designed and certified by a registered professional engineer or registered profes- sional sanitarian. The beds must be located outside the flood-prone area and not within areas subject to inundation or erosion by flood waters or rainfall runoff. An applicant for a permit to install a sewerage system shall consult with the local flood plain ordinances administrator, county engineer, State High- ways and Public Transportation Depart- ment, nearest river authority, Farmers Home Admirtis~tration, Federal Emergency Man- agement Agrncy, and any other officials who may have information regarding the poten- tial for flooding at the site of the evapo- transpiration beds. (B) Evapotranspiration bed con- struction features. The following factors must be considered in the design of evapo- [ranspuation beds: annual mean rainfall and wettest month of the year, annual mean eva- poration rate and monthly min'unal rate, growing season variations, native grasses and shrubs available for cover, absorptive capaci- ty of the soil surrounding an unlined bed, and site conditions, including varying sun- light and air movement. (f) There is great variation in the types of plants grown in different parts of Texas, as well as differing transpiration rates in different plane. It would be hazar- dous to generalize N making specific sugges- tions on design criteria for systems depen dent on evapotranspiration for successful operation. Specific recommendations on ap- propriate types of vegetation to use must be obtained from knowledgeable organizations such as the United States Department of Agricul[me-Soil Conservation Service, Texas Agricultural Extension Service, or reputable plant nurseries. (iiJ Evapotranspiration beds aze constructed in impervious soil or soil with very high absorptive capacity. When the soils have a very high percolation rate, less than five minutes per inch, liners approved by the local regulatory authority must be construc- ted to guard against the possibility of waste- water discharging through the sail (fissured rock or gravel) and contaminating streams, lakes, or shallow groundwater. Impervious liners may consist of reinforced concrete, 20 mil minimum single layer thickness plastic, or rubber liners. All must be repairable in the field. Liners are not required in slowly permeable soils (having permeability of less than 10 centimeters per second) and should not be used since some of the wastewarer may be absorbed inm the soil and wiil help [O red9Ce 'h.C J'+TG!! "~cIX:~":..^.1CIrd'ln^. Toad. An evapotransp'vation system shalt be designed using the following parameters. (1) )lads may be designed in any configuration subject to the approval of the permitting agrncy (square or round, for ex- ample), but the total number of square feet of bed area must be determined by the for- mulas in subparagraph (C7 of this para- graph. (II) At least two beds must be constructed with valuing arranged to allow the effluent from a sewerage unit to alter- nate betwern each bed. When one bed be- comes saturated (top of bed remains moist) the valuing must be operated to allow efflu- ent to flow into the alternate underloaded bedding. In order to determine the water le- vel in the beds during tee, an inspation port shall be installed in each bed. Inspection ports shall be designed to prohibit access to the bed bottom by insects, small animals, and unauthorized persons. (III) The beds shall be con- structed as shadow as possible with a depth ranging from 18 inches to a maximum of 36 inches. This is necessary to keep the beds aerobic and prevent dogging. Treatment tankage should be installed as high as prac- tical to permit shallow bed construction. (IV) It is possible for a liner to be damaged after it has been cove: ed, caus- ing the bed to leak sewage without showing at the surface. At [he discretion of the per- mitting agency, each bed may be required to have a separate monitor system installed in a manner that will facilitate co8ecvon and sampling of effluent leakage from a raptured liner. The monitor system is designed to of- fer ameans ofdetecting liner failure through periodic sampling, which will help ensure the protection of the environment. The rntire monitor system must be assembled and ready for approval during a single inspection. No sand shall be put in place es a wshion until the monitor system has been inspected and approved by the licensing authority. (V) Evapotranspiration Bed. Its design features, as illusvated in Figtue 6, are as follows. (-a-) Atl piping must be three to four inches in diameter. All perforated collection lines of an evapotranspiration bed mo[[[or system must have a minimum crush strength of 1,500 pounds per linear toot. The standpipe and sample sump must be of Schedule 40 polyvinylchloride or stronger. All connections shall be glued or rubber gasketed joints with the exception of the in- truder resistant standpipe cap located at finished topsoil grade. Perforations in the collection lines must face downward, with the two rows of perforations equally offset perpendicular to the ground. (-b-) The end(s) of [he per- forated collection line(s) shall extend to within two fat of both opposite ends of the bed, measured at the bed botwm. (-c-) An evapotranspiration bed whicS rs 20 ".'eat wide or Tess shall have ......^.im~.~ n of oue cel!:,rion :ine •.chich must l`~ ~~~ '~:~preJ ,'Zu1es be located centrally, down the length of the bed. An evapotranspiration bed which is greaur than 20 fact but equal to or less than 40 feet in width, shall have a minimum of two collection lines. These lines must be equally spaced (within approximately one foot) from the edge of the bed to pipe, and from pipe to pipe, installed parallel down the Irngth of the bed. The two collection lines must be jointed by a perforated header line. As indicated in item (-b-) of this subclause, the header Gne shall be within two feet, and parallel, to the edge of the bed measured at the bed bottom. Monitor systems for lined evapotranspiration beds wider than 40 feet shall be designed as required by the permit- ting agency. (-0-) The co0ection line system must maintain a minimum fall of 1/16 inch per foot toward the standpipe/sump assembly. (-e-) The collection line(s) shall tee into a solid wall standpipe which must have a sampling sump below the bottom of the tee. This sump shall be eight to 12 in- ches in depth, measured from the bottom of the Tee. A cap or plug must be glued to [he bottom of the sump to provide a watertight connection. The top of the standpipe shall be flush with the finished grade of topsoil, and shall be covered with a intruder resis- tant, removable access cap. A minimum three inch wide by three inch deep dry moat shall surround the standpipe cap to facilitate ease of cap removal and replacement. (-f-) The pi[ bottom on which the collection line(s) shall be placed must be an impermeable surface, graded to provide a minimum fall of I/8 inch per foot toward the collection line from either side. This will result in an impermeable shallow va trench for the collection line to rest in. (-g-) The collection line(s) shall be located within the sand cushion required under lined beds. The minimum four inch sand cushion depth wID inaease as it follows the grade fall of the pit bottom toward [he collection line. The backflll material around the standpipe should consist of sand or san- dy loam. (VI) Rock media that is general- ly one uniform size from 0.75 to two inches shag be placed on the bed bottom [o a depth of l2 inches or less depending on the overall bed depth, after the liner and sand cushion are plead over the monitor system. (VII) The top of the distribution pipe must be Flush with the rock media and adequate to provide for uniform distribution of effluent. A 12-foot maximum separation between pipes and no less than thra feet separation between bed walls and [he pipe is permissible. The bed bottom and the pipe must be level. (VIII) A water permeable sand barrier (butcher paper, newspaper, or geotextile fdter fabric) is then placed over [he rock. Sand is then added to fill the bed to within two inches from the top. J.a1v !U. /987 /Z Texl2eg ?734 (IX) In order to provide conti- nuous capillary action in the sand, wicks shall be incorporated in the rock media. Wicks are simply sand structures which pe- netrate through the rock media to the bot- tom of the bed (See Figure n. The total wick azea shall be 10%a to 15% of the bed sur- face area and shall be uniformly spaced throughout the bed. Wicks may also be con- structed by simply grading furrows in the rock media in between the distribution pipe. In areas of the state where rock media is dif- ficult [o obtain, the total amount of rock A = 31,000 (1 + B) EA - 1/2 RFRA B =Total ntsnber of bedrooms (8=2 for minittnmt residence) ' EA =Mean evaporation rate in inches per year (See Table VII) RFRA =Mean rainfall rate in inches per year (See Table VII) A = 310 O EA - 1/2 ~''RA may be reduced by filling the initial 12 in- ches of the bed with warse sand (two millimeters) and placing rock media only around the top, bottom, and sides of the distribution pipe to form an 18-inch en- closure, as indicated in Figure 7. (X) After the sand is in place, the final two inches of bed volume are filled with sandy loam and mounded with a downward slope of two to four percent. (XI) Final bed construction con- sists of covering the surface of the bed with Where A =Total area of both beds (To find orie bed area divide A by 2) For Non-single family residential situations: Where Q = Average daily flow into the system, expresse3 as Gallons per day (See Table III). vegetation having good transpiration proper- ties and providing for the most s[ormwater diversion that is practical. (C) Bed siting. Evaporation and rainfall data for various areas of the state are listed in Table VII. Additional data may be found in Report 192 and Report LP192, published by the commission. After the reader considers subparagraph (B) of this paragraph, the bed area may be approx- imated by using the following formulas: Evaporation and rainfall data for various areas of the State are listed in Table VII. Additional data may be fourrl in "Report 192" and "Report LP192", published by the Cotnnission. (D) Plants and grasses for tran- spiration. The bed surface shall be covered with vegetation designed to take maximum advantage of transpiration, depending on the season and site's location. Evergrern bushes having shallow root systems can be planted m the bed [o assist in water uptake. If grasses are used which have dormant periods, steps shall be taken to provide appropriate vegeta- tion on the beds during these periods. Overseeding with winter grasses is commonly used to provide year-round transpration. (E) Geographical location of in- stallation considering rainfall data. Some areas of the state with high annual rainfall aze not well suited for the installation of evapotranspiration systems. Counties in the eastern part of the state in which the annual rainfall excteds the annual evapotranspva- tion rate should only utilize this tyde of system as a last resort and with considerable design conservatism. (5) Pressure dosing systems. (A) Description. A basic pressure dosing system must consist of an approved sewerage system, an efluent holding tank, -•~ ^:a -erne.' fnta'~e '!ectec ~u:-:p .viic,^s „cti•; tired S_; a ~uat or pro- grartuned starVstop switch, a solid wall force main, and perforated distribution piping which is installed within the absorption area. The effluent pump must be capable of an operating range that will assure that effluent is delivered to the most distant point of the perforated piping network, yet notbeexces- sive to the point that blowouts occur in shal- low systems. The programmed start/stop switch should allow the pump to operate at least three times during the 7A-hour day. A high water alarm, on an electric circuit separate from [he pump, must be provided. After the alarm activates, the effluent holding tank shall have remaining capacity of Sb0 gallons for gesidences and 1,000 gallons for businesses and institutions. The number of perforations per Irngth of pipe and the number of pipe Irngths used per ab- sorption area must be adequate to assure uniform liquid distribution over the entire bed area. (B) Application. Pressure dosing is an appropriate method of conveying ef- fluent from a treatment site that is at a lower e'.evation than the disposal site. It is also ap- •mriare w^err ~.r^cr~a! ~, i'>n .Narer 'ab:es Cx15[ V[ 'NhC;'. :nC sGL :fta.^.i!: hiC :^C55 'S from two [o four feet to solid rock. In these situations the system must be oversized sub- stantially to promote the effect of evapo- transpiration. Commercial establishments may need to use continuously staged pressure dosing if their Flow rates vary greatly dur- ing their business hours. The United States Department of Commerce (USDC) has pro- duced University of North Carolina Sea Grant College Publication UNC-582-03 which discusses the design of a low pressure dosing system for subsurface disposal of treated sewage. It is a 31-page document that was published for public use in May 1982. Inquiry on how to obtain a copy should be sent to United States Department of Com- merce, Washington, D.C. 20460. At the discretion of the local regulatory agent, pressure dosing systems must be designed by a registered professional engineer or registered professional sanitarian. The EPA Design Manual, discussed in scbsection (a) of this section, also has information. Although these publications are referred to for design information, the department does no[ adopt them or any other technical li•erature. (GI NWUr,J e~'St2T.,. ' .. ---... __. ....: 'a, !"F- Trr_.; 2^^.. .,. ~ ICJ (A) Physical descriptiop. A mound system is comprised of a layering of sand fill, gravel, perforated pipe, and top sorb. The layering begins in a two-[o-three- inch excavated area of natural ground and develops above the mmund line approximate- Iythree feet. For greatest efficirncy, its shape is rectartgular. The small diameter perforated piping must bepressure-fed, as pressure sys- tems have greater control over application rates. (B) Application. The purpose of [his type of construction is to overcome adverse conditions at the disposal site such as a high groundwater table, shallow soil, impermeable soils, and high po[rntial for flooding, for example. In general, the mound is constructed of a high quality soil which is brought in from another area, Since there is a potrntial for leakage from this type of system which could result in the surfac- ing of sewage azound its perimeter, i[ is not recommended for use except as a last resort. If approved by the local permitting authori- ty, it may be used in an effort to improve the operation of a malfunctioning disposal system. Applications of effluent to a mound system depend upon the selection of fill materials used, the absorption rate of the natural ground, and depth to the shallow groundwater table. Design information for mound construction may be obtained by or- dering the publication list of the Small Scale Waste Managemrnt ProjeM, 1987, which is available from the University of Wisconsin, Room ?A0, Agricultural Hall, Madison, Wis- consin, 3371X. (7) Gravel less drainfield piping. (A) Appropriateness. Gravel less pipe may be used in place of conventional gravel-filled Vench systems. The regulatory authority and permit applicant shall carefully consider all site conditions and circumstances before arriving at decisions regarding pipe diameter selection, Vench dimensions, depth of the installed pipe and suitability of on- site soil as backfill material. (B) Physical description. Gravel less pipe generally consists of eight-inch or 10.inch diameter corrugated polyethylene pipe having two rows of perforations located approximately I1A degrees apart along the pipe's bottom half. The pipe is enclosed in a layer of spunbonded nylon filter wrap. Pipe shall meet American Sudety for Testing and Materials, ASTM F-667 Standard Specifications, for large diameter corrugated high density polyethylene (ASTM D I7A8) tubing. Perforations shall be y: inch diameter in 10.inch diameter pipe and 3/8 inch diameter in eight-inch diameter pipe. Perforations shall be arranged and spaced so that only one hole exists in pch inner cor- rugation. The filter cloth must meet ASTM D 3776 and ASTM D 1682 sperifiptions for weight and grab strength. Its burst strength and air permeability must mrt ASTM D 3786 and ASTM D 737 specifications, resrectively. Installations must be in accor- ......~_ ,vi[: [ne clue manuiue[urea' ins[ruc- [ions. However, the system installer is dutioned against surtounding the pipe with native soils having percolation rates slower than 30 minutes per inch or htdrn with very fine soil particles that might plug the filter wrap. (C) Design parameters. The de- sign of anabsorption bed, absorption [tench, or evapotranspvation disposal field utiliang this product shall be based upon the same parameters that aze used in the design of more conventional rystems. §301.14. Disposal Alternatives/Special Ap- plicatians. (a) Greywater systems. Generally, blackwater and greywater are approximate- ly 40% to 60% of the total domestic sewage flow, respectively. Subsurface greywater systems may be utilized with disposal of blackwata through a split system only under the following conditions. (t) A greywater disposal system uti- lizing anything other than wnvrndonal sewage vestment and absorption beds or Venches shall be designed and certified by a registered professional enginar or reg- istered professional sartitarian who cart pro- vide to the permitting authority evidrnce that the system complies with all appropriate state regulations and local governmrntal regula- tions. (2) If flow restricting showerheads and faucet aerators are utilized throughout, a IO%s reduction in greywater disposal Vench, absorption bed, or evapotranspira- tionbed size will be allowed when a residrn- tial Breywarer system is incorporated into the disposal system design. The maximum allow- able reductions in field size are determined by the type of system and the extrnt of wa[ersaving fixture usage. (b) Composting toilets. The com- posting toilet unit must be listed with the NSF. The NSF seal on a particular unit in- dicates its ability to meet the requvements of the NSF Standard Number 41, relating to wastewater recycle/reuse and water con- servation devices. The liquid waste From the composting toilet unit must be disposed of through an approved subsurface disposal system. (c) Sewage recycling systems. For small on-site applications, sewage recycling systems are very limited in types and ppa- bility as follows. (1) On-site sewage recycling as flush water for urinals and commodes in cornrner- cial and institutional projects maybe possi- ble when advanced tertiary treatment pro- cesses are rngincered into designs that meet or exceed NSF Standazd Number 41 testing and certifiption requvements. An approv- able design will be permitted only after the supplier and user of the recycle system enter into apost-installation inspection, mainte- nance, and repair agreemrnt that satisfies the permitting authority. (2) Proposals to recycle highly re- fined sewage !r usa ouaiu: )rajr:: bull (~ $ Adapted Rules ings such as for surface landscape irtigatioo will be subject to requiremrnts indicated in §301.1 l(f) of this title (relating to General Procedures and Information) and by the Texas Water Commission in 31 TAC §§317.1-317.13 (relating to Design Criteria For Sewerage Systems). §301.15. On-site Sewerage System Maintenance and Water Conservation. (a) Anon-site sewerage system should not be Vested as if it were a sty sewer. Economy in the use of water helps prevent overloading of a sewerage system that could lessrn its usefulness. Leaky faucets and faul- ty commode fill-up mechanisms should be carefully guarded against. Garbage grinders can pox a rapid buildup of sludge or scum resulting in a requirement for more frequent cleaning and possible system failure. The ex- cessive use of garbage grinders and grease discarding should be avoided. (b) Water conservation measures that will reduce the load on the onsite sewerage system include the following. (1) Showers usually use less water than tub baths. If showers are used, install a shower head that restricts the flow from about five gallons per minute to approx- imately two and one-half gallons per minute. Try taking shorter showers to save water. (2) If you take a tub bath, reduce the level of water in the tub from the level to which you customarily fill it. (3) Do not leave the water running while brushing your teeth or washing your hands. (4) Check commodes for leaks that may not be apparent. Add a few drops of food coloring to the tank. Do not flush. If the color appears in the bowl within a few minutes, the toilet flush mechanism needs adjustment or repay. (3) Do not use the toilet to dispose of cleaning tissues, cigarette butts, or other Vash. This disposal practice will waste water and also impose an undesired solids load on the treatment system. (6) Reduce the amount of water used for Flushing the commode by install- ing a toilet tank dam or filling and capping two one-quart plastic bottles with water and lowering them into the tank of the com- mode. Do no[ use bricks since they may crumble and pose damage to the fixture. If anew toilet is installed, install a two and one- half gallon (for less) commode rather than the convrntlonal three-to-five gallon fixture. (7) Try to run the dishwasher with a full load, whenever possible. (8) Avoid running the water con- tinuously for rinsing kitchen utensils or for cleaning vegetables. (9) Use faucet aerators that restrict flow to no more than 2.75 gallons per minute [o reduce water consumption. (10) Keep a container of drinking water in the refri¢erator instead of running _ ` lulr'/0. l9Ri 12 TexRe~ 224! (11) Insulate all hot water pipes to avoid loag delays of wasted water whi]e waiting for the heated water. (12) Repav leaky faucets. (13) Ask your city, county, or local government about their programs to con- sme water and how thry can help you save water. (c) Septic tanks shall be cleaned before sludge accumulates to a point where it ap- proaches the bottom of the outlet device. If sludge or scum accumulates m this point, so- Gds wilt leave the (ank with the liquid and possibly cause clogging of the perforations in the drain£eld line resulting in sewage sur- facing or backing up into the house through the plumbing f[xtures. (d) Since it is not practical for the average homeowner to inspect his tank and determine the need for cleaning, a regular schedule of cleaning the tank at two-[o-thcee year intervals should be, established. Com- mereial cleaners aze equipped to readHy per- form the cleaning operation. Owners of septic tank systems stud! engage only persons registered with the Texas 1epartment of Health m transport the septic tank cleanings. (e} 17o not build driveways, storage buildings, or other structures over the sewerage system or its disposal field. (f) Chemical additives or the sorelled enzymes are not necessary for the operation of a septic tank. Some of these additives may even be harmful to the tank's operation. (g) Soaps, detergrnu, bleaches, drain cleaners, and other household cleaning materials will very seldom affect the opera- tion of the system. However, moderation should Fx exercised in [he use of such materials. (h) I[ is not advisable to aIIow water softener back flush to rnter into any portion of the on-site sewerage system. (i) The liquid from the sewerage system is still heavily ladrn with baceria. The surfacing of this material constitutes a hazazd to the health of those that might come into contact with~it. (j) For residential systems, up to a 20% reduction in the siu of the blackwater absorption beds or trenches will be allowed, or up to a 10% reduction in blackwater evaporranspvation beds will be allowed, if approvable watersaving blackwater futures are made a part of the sewerage system design. §301.!6. Unsatisfactory On-Site Dirposa/ Systems. The construction and use of those systems not in accordance with she Texas Sanitation and Health Protection Law, Ar- tide 4477-1, mnsHiutes a violation. The department considers the following on-site disposal systems unsatisfactory because they trnd to create nuisances and other conditions prejudicial to the public health. (() Cesspools. Cesspools were once commonly used in rural areas for disposal of domestic wastes. Cesspool designs con- sisted of constructing a pit into permeable soil and curbing the sides of the pit with open-jointed material to the bottom of the pit. Raw sewage was discharged directly in- to the cesspool and the organic material anaerobimity decomposed while the partially treated wastewater was absorbed by the ad- jacent perraeablesoil. Since the threat of in- jury to public health is greater when raw or partially treated wastewater is in direct con- tad with the absorptive soil, this method can no longer be considered as an approved means of sewage disposal. (2) Bore holes and injection wells. (A) Bore holes and injection wells used for disposal of domestic wastes generally consist of a drilled hole Beater than four fee[ in depth and varying in diameter from eight inches to 36 inches or lazger. Usually, the holes are filled with crushed stone and are dug to a depth which intercepts a permeable soil layer. Raw sewage is dis- chazged into these holes directly or after detrntion in a septic tank. (B) The use of bore holes or in- jection wells for domestic sewage disposal is not an approved disposal•method because it is possible to wn[arttinate underground water. Injection wells approved and permit- ted by the wmmission are acceptable to the deprutmrnt. However, injection wells used for private sewage disposal, as defined in §301.11(b)(20) of this title (relating to General Procedures and Information) are not subjat to regulation by-the commission. Their use wiG not be approved by the depart- ment. variations of bore hole design such as soil substitution methods may be ap- proved as stated in §301.1 t(f J(2) of this title (relating to Genera) Procedures and Infor- mation). (3) Seepage piu. (A) Seepage piu are rock-filled or lined piu dug to a depth in excess of four feet and located at the end of a septic tank absorption field system. The piu are grneral- ly used to dispose of wastewater which would normally not be absorbed in the ab- sorption field and would otherwise surface. (B) Seepage piu are not an ap- proved method of wastewater disposal for 'the same reasons that apply to bore holes and injection wells. Subsurface water con- rnminar;on ntayoccur with these systems and [he anaerobic bacteria present in the waste- water may eventually cause plugging prob- lems in the seepage pit. Sec. 301,17. Tables and Figures (a) Table I. 'The following table covers the minimum required distances 1n feet for conventional systems: TABLE I MINIMUM REOUIREO DISi'ANCES IN FEET FOR CON VENTIONAL SYSTEMS Sewage Lined Soll Sever Pipe To Treatment Evapo. Absorption With Watertight From Tanks Beds Systems or Joints Unlined Evapo. Beds Private Water Wells, Underground Cisterhs and Pump Suction Pipes 50+ 150+ 150+ 20+ Public Water Wells Water Supply Lines Streams, Ponds and Lakes Sharp Slopes, Breaks Foundations, Structures and Surface Improvements O..nron~'% __ne9 50 150• 750 20 to t0 to 9 50 75• 75 20 5 var. SOf• S 5 5 15 - i~ )Q 1C - °_?_~ ?'-^. !sL Ih. 1987 Texas Register ~- (~ (c) Table III. The following table covers individual usage rates in businesses and institutions: TABLE III INDIVIDUAL USAGE RATES IN , BUSINESSES/INSTITUTIONS This table may be used for estimating gallons of daily sewage flow per person to determine minimum tank capacity requiements, unless actual water usage data is available and has been carefully checked by the designer of the proposed system. TYPE OF ESTABLISHMENT GALLONS/PERSON/DAY Airports (per passenger) , 5 Apartment Houses 50 Boarding Schools . 50 Churches (per member) • • 5 Country Clubs (per resident member) 100 Country Clubs (per non-resident member present). 25 Day Care Centers (without kitchen) 15 Day Care Centers (with kitchen) . 25 Drive-in Theaters (per car space) 5 Factories (gallons per person per shift, exclusive of industrial wastes) 20 Hospitals 200 Hotel .. 80 Institutions other than Hospitals 100 Laundries Self-service (gallons per wash, i.e., per customer). 50 Lounges (bar h tables) 10 Mobile Homes 75 Motels 50 Movie Theaters (per auditorium seat) 5 Office Buildings . 15 Parks (without bathhouse) 5 Parks (with bathhouse) • 15 Restaurants (24-hour full service) 70/seat/day Restaurants (breakfast/lunch or lunch/dinner) 35/seat/day Restaurants (fast food - paper plate service) 15/seat/day Schools without cafeterias, gymnasiums or showers 15 Schools with cafeterias, but no gymnasiums or showers 20 Schools with cafeterias, gymnasiums and showers 25 Service stations (per vehicle served) 10 Stores (total per day per washroom) 400 Swimming Pools and Bathhouses 10 Townhouses (with clothes washer) 50 Travel.Trailer/RV Parks ~. 50 Vet Clinic (per animal) . 10 Work or Construction Camps (semi-permanent) . 50 Youth camps Cno showers or meals served) 15 #"iota: Offices without Food Service or Bathin;5 Facilities, with Restrooms Equipped with Toilets Requiring 1.5 Gal'_on per Flush or Less, ar.d Au ,o ^:a tic Cutoff Faucets 6 'C -_ Easement Lines t 1 5+++ _ Soil Absorption Systems 5 5 20 - Swimming Pools 15 15 15 - •Nhen a leak detection system, as described 1n Sec. 301.13.(c)(3)(A)(Si)(IV)(-a-)is used, the minimum required distance is 50 feet to existing private water wells, cisterns and pump suction pipes. Var. These minimum required distances may be varied if an innovative lined system Ss required Dy the permitting authority to be designed by a Registered Professional Engineer or Registered Professional Sanitarian. •+The absorptipn system's bottom must be a mint mum of 50 feet from any break or outcropping ledges, unless it Ls designed by a Registered Professional Engineer or a Registered Professional Sanitarian having hydrogeological data of the strata below the system's site. Greywater disposal areas may be installed to within 25 ft, of the slope face. +++A drainage Easement having sloped sides greater than 30f or grade breaks will require adherence to the 50 fool criteria indicated by ++. .this distance may be reduced to a minimum of 50 feet, for existing p.^ivaLe water wells only, Sf the space between the existing private water well casing and the surrounding ground is filled with cement slurry that is pumped through a tube Lhat extends to the required depth of sealing. This depth shall be at least two times the horizontal encroachment measurement but not more than the depth to the water producing strata. A three foot square by six inch thick concrete slab shall be poured around the casing. (b) Table II. The following table covers septic Lank minimum liquid capacities: TABLE II SEPTIC TANK MINIMUM LI pUID CAPACITIES NUMBER OF BEDRUOt1S SEPTIC TANK CAPACITY (Gallons) TNO Or less ~ 7c~D Three 1,000 Four 1,250 For Each Additional 250 NOTE: The Inside Liquid Depth Of The Tank Shall Not Be Less Than 30 Inches. See Table VI For Calculating The Number Of Bedrooms Based On Dwelling Living Area. Consideration shall be given to increasin3 total Lank capacity if extensive use of kitche^ sank waste grinderi disposals is anticipated. ~ D~ :y .?c,w.>~~ .', u:=s ?-.1~ ;p. ;9~7 12 Trs,~eg 223 (d) Table IV. The following table covers selection of proper subsurface disposal methods: TABLE IV FLOW SHEET FOR SELECTING PROPER SUBSURFACE DISPOSAL METHODS I Conduct Site Evaluation ~ s Conduct Percolation Tes[ on Lo[ Test Range From 5 Minute/Inch To 70 Minute/Inch Test Range From 30 Minutes/Inch To 60 Minutes/Inch ~Calcula[e Length of Urainf ie ld Calculate Size of Absorption Bed Site Not Accep Test Rate Over 60 Minutes/Inch or Less Than 5 Minute/Inch Calculate Size Inves[iRate of Evapotranspiration Beds AlSewaaEive using a water balance Disoosal Systems LoC Size Lo[ Sfze Lot Size OK Lot Size Lo[ Size Lo[ Size OK P'or Too Small For For Bed Too Small OK Drainf fie ld Dra inf field Too Small For Bed For Beds For Beds i ~ Install Construct l.'a ter Saving Absorption Devices bed Re-calculate Lot OK Lo[ too Small Purchase Additional Property for Beds Construct Evapotranspiration Bed ~, ., N d 4i i rv Q d a 1 y v 3 K 'tl 91 4 b e ~' v fl (e) iab.~e V. 'ihe f~`.louing table covers criteria Cor soil absorption of sewage effluent developed for site spc~ific eval uattons: TABLE V Cd(TG9iA FOR SOIL ABSORPTION OF SEl0.CE EFFLUENT DEVELOPED FOB SITE SPECIFIC EVALUATIONS Cl asslfication Sita Provisionally Charecterist Lc Suitable Suitable (ll Not Suitable Topography Slopes 0-155 Slopes 15-30f Slopes greater than 30F Caeplex slopes. Subsoil Sandy soils, Clayey soils with low Clayey soils with high Texture Loany soils shrink-swell potential. Shr In k-well potential. Subsoil Angul ar or subangular Platy structure. Mea the red Structure _ blocky. rock. Massive clayey soils. Soil Depth Neethered rock or 'leathered bedrock or ileathered rock or consolidated bedrock consolidated rock from consolidated bedrock less greater than 4B inches 36 to 48 inches below than 36 inches below below ground surface, ground surface ground surface. Restrictive None within 36 inches Restrictive horl zon within Layer of the ground surface 36 inches of the ground surface or below the trench bottom. Soil No drainage mottles Drainage mottles (chroma 2 Drainage within 36 inches of or less) within 36 Snches of t)ie ground surface i the ground surface. Flood Sng Areas subJect to a possible flood. Depressional areas without adequate drainage. Soil Greater than or Less than or equal to Per,neability 5 min/inch but 5 min/inch or less than or equal to greater than 60 min/inch. 60 min/Snch. Unselecttve fill material groundwater, Soil may be reclassified from unsuitable to provisionally suitable under certain conditions using acceptable site or system moll Citations. iJ e n' i E- r c c r. ,r-~ G.. :, (C) 'Cahl=_ VI. '(Yie following table covers absorption trench axf bid sizing for single family residential dwellings: More '(tai 12 Too Treat far Considaatim 4 - 12 0.6 2 - 4 0.5 7.3 - 2 0•A t.o - 1.3 0.3 less Than I.css lhai 1.0 D•3 AB90RPfI0N lttF2141 ACID EFD SIZIIG FCR SIN3E FAMILY RFSILfTfI'IAL LM11.IlCS Average Percolatim Rate Sewage Appllcatim Soil Textu4 Minimun Bottom Area Mlnirtxao Bohan Arm (Minutes/Irxiil Rate, Ra (See Table VIII l6DA GSq. F2.) Far a One Fa Fach Additia:al Soli Textural ar 11+o Bedroom Fb:+se Bed~'°® (`~•~•~~) Classificatiore) MSrxfies Per Inds Indies Per Her Gallore pa' Sa Ft. Per Day Less Tta: 5 5-t5 16-30 3t - u5 46-60 tore Ttar 60 TAS11•: n SardiTi'avel T}~di Bed TraK'h Bed Sections ~an Alternative Systees Sandy ~~ ~ 750 200 SsdY Clay r~p0 900 250 Silty Clay ~ " 1125 ~ Clay Ian 800 1500 400 See Sect ions on Altern ative Systans Clay 300 400 500 Minlmao trench bottrn+ area is calvilated W include capacity far wastSr:g mac3:irie wastewater, orgade material lYan garhage ~'lyders, and infiltratim fiom ralnCalL Required minimum spacing between paallel omveitianal absorption Lrerdrs is 3 tramp uidtt~s. +yR:m dwellings consist of a large livL:g arm relative to tt:e nuaba of designated bedrooms, the following guidelina9 should be used to approximate the tra«;h arm: less than 1.500 sq. Ct. - llse tra:rh arm for two bedroom Fnuse 1,500 sq. ft, to 1.900 sq. tt. - ilea trarh area for Uvee bedroom house. For end: additional 800 sq, ft. -Add traxd~ arm ~ to are bedroom This criteria 1s valid fa mrmal eater' oonsrmdtien bf an ~a'age touselmld oocWerx:y and is rot applicable to collective sewage systen desl~. a r, N Y a F N n a 0 a 1 v .~ a„ a `n. .e ~• ~rt irJ 'N (g) Table VII. The following table covens mean pan evaporation and rainfall: TABLE VII MEAN PAN EVAPORATION AND RAINFALL E RFR A A Mean Mean Evaporation Rate Rainfall Station (Inches/Year) (Inches/Year) Abilene 75.Oa 23.8aa Amarillo 87.9 20.28 Austin 70.0 32.49 Beaumont 47.8 55.07 Brownsville 56,0 25.13 Canyon Lake 80.8 33.19 Corpus Christi 67.Oa 32.0*+ Daingerfield 74.2 46,12 Dallas 85.0 35.94 El Paso 106.5 7.77 Fort Stockton 105.6 11.85 Houston 48,7 48.19 Lake Sommerville 71.7 37.45 Laredo ~ 87.Oa 21.Oaa Lubbock 88.7 18.41 Lufkin 51.0* 43.0+a Midland-Odessa 85.0* 13.Oaa San Antonio 70.Oa 30,Oa• San Angelo 84,0• 19.Oaa Temple 68.2 34.00 Tyler SS.Oa 42.Oaa ;Jvalie 72.0+ 25.Oaa 'dichita Falls 73.Oa 27.Oaa a Interpolated From Map, P. 66 Climatic Atlas of Texas as Interpolated From Map, P. 18 Climatic Atlas of Texas l2 TasBez :Z'3 July '0. IJA7 Te»as Re,;ister (h)' Table VIII. The following [able covers USDA Soil Textural Classifications: TABi.E VIII ao Clay - Smaller than 0.002 millimeters in diameter Silt - 0.05 [0 0.002 millimeters in diameter Sand - 2.0 [0 0.05 millimeters in diameter 2~ '3 .-coprz~; :4~b.; l11: I0. 193' 12 TexReg 2249 O O O O ~ J J ! 0 O O O O V ' ~E ~CEMi S~NO (i) Figure 1. The following figure Illustrates a two compartment septic tank and is not intended to serve as an engineered design for construction purposes. Ground Half To Two total Tank L 'Clean 10' Clean Out Depth May Vary, But Not Exceed 12 inches unless a riser is installed on each cleanout and the tank manufacturer allows it. 10• Clean Outer ~ "' " Tee Fltting + Inlet ~ Llquld Surface Outlet N ~{ 3' _ 25 D Outflow pipe must tre $ I Scum to at least 3 ^ lower 3 ft Min. ,50 D than Inflow pipe. Tee Fitting SPACING p o Tee Fitting a Alternate Tee Fitting--/ I I I I ` ` ~..~...ll I I F a Sand Cushion ~ ~~ 0 n H H L M. Fr ry 1 N N 'ry ~1d 1 ~1 ~`~ 1 j x ,~ `~ 4 q' ~' N ti a. b a. 0 ti 4 tanks in series Snd Is not tn' iHusaes 9 tWOr construction Purpose . wing use n lil te9 ded to serves as an efn9'neered r ~tppGE OttOUNP SU th MaY Vahe~un ess ao~~ and Exceed 18 inon each cteallows It. ~, is tinstall manutaeturer a • is the tank Brame teveane an Out bothlanks• i0 G1e n Out Oultlow The first tank o th~r h tankse °ng•half to tw { bo 10' C1ea 3, Mtt1. a shall be total volume ° puttlow Sip tower ~-- .25~ at least tanks ..~~ To nttrst ~ 2" ~~ nuidSurtaee •5p,~ i~f1oW Prpe. Inflow TeeFitUn9 TeeFittln9 Tee .D 1N i 1 Sand~ushion (k) Figure 3. The following figure illustrates soil absorption trench construction details and is not intended to serve as an engineered design for construction purposes. SURFACETO DRAIN 36' Max. :~,:.-.::;.,z::~: 16"Min. "~. - '~;~. 12' ;:~ 12+-36' SANDY LOAM 3'_10' Perforated Pipe For Effluent Disposal 6' MIN. 12" MAX. Multi layer Paper or Geotextile Fabric ~ Cd ~~ ~; 'F; 4' `ct of x 0 O "~ n~ V- n~ N Or d Q; H 1 f.~ (I) Figure 4. The following figure illustrates a septic tank system for sloping ground without sharp slopes or grade breaks. SANDY LOAM ~--- Earthen plug Solid wall piping ~-GROUND SURFACE Z~ ~ Adopted Rules luly I0, l987 !? TesRe~ 2'S? The septic tank and perforated piping shall be installed level while compacted earthen plugs shall separate the solid wall piping from the perforated piping and gravel. (m) Figure 5. The following figure illustrates sgil absorption bed details and is not intended to serve as an engineered design for construction purposes. Sewage Treatment Unit Noncorrosive, Non-Jamming Leakproof alternating flow valve A ~ __-, Distribu- p lion Pipe I 1 n n ~ °~ ~ 1 Distribu• Min p lion / Pipe i A 9 r Plan View O1 Dual Bed System r SANDY LOAM 6" min Do not use rock or clay 72" max = rL~ for backflll is . ~ ~ r Geotextile Fabric or p'~`"'"y 36" MA ~ " SAN : ` Butcher Paper 24 Min. 12" + i + GRAVEL 3'=10" Perforated 6'-12' Pipe for Effluent Sand Wick Disposal Section A-A -~9 - Illustrates a leak monitor figure Serv as an en9lneered (nl Ffgu~e 6a des nlo~WntendeUrPoses-e system construction P design for PIPE. ~ pERFORA~DE SL GH OR OWARD PIPE WITH GRA 1 ~~ . / ~\ I / ~~ .\~ T ` •~ ~y ` f /T.,Y/~ /~ /,i /~/ p% \ `~ / ~ t ~~ • - . SJy / ` ~ / ~ - CR~SyEO SP No , AY6A - . ~../ C ~ y i ~. ~ LINER ~ ~A1' . \ - IMP - FR<<,. µ10N5 g t ~ ~,_\: 4Aµ1NlMUNITµIGKNES - %:: v, ~, N u a x E I ` a .. 0 ~ti d a tv ~-.. ~,... , \ M ,.` ,~ ,_,., ~. •. r, REM ~ A5 GRADE LEVEL SAM ~i .i~ a! i ~- ~~_ -' , ~ ~ ~ -~ PLUG i j ical evapotranspiration bed sneered design for construction fi ure fliustrates a tYP an eng (ol Figure 7. The following 9 cross section and is not intended to serve ~ 2" 3"pERFORATEO Purposes. Geolextile Fabric pIPE or Butcher Paper ~ MON1TORlNG Layer `, ..,:..:. SURFACETO DRAIN SLOPE ~ ' ` SANDY LOAM - Sand Cushion Sand ~ `~ 6: \... \ \ \. Band ~ + , .. - • .. , t ~ `:C ed • 18" MiN ~ , ~ ~ ~ ' ~ ~ ~ ~' r ~ rush ~ . ;; _' ~~ Sand ~;.,. ~ ~ Stone r 36"MAX. -• -.. ~:~:: .,% .F .: ~~ Ydlck ~'~~ ~ r`~~~ ~~ '`fi'r`"~ ^r ~. . --,. ~ ~ ~` i :; 12' r r ., °: w. ~ s. •. ' g ti MAX. - _ ~ ;,. '`` • ` ' • SPACING 3,10• plstrlbution --- pVC Pipe 12 ft SPACING Liner • 81t t° Thickness Alternate 2p MIL Minimum Crushed Stone Bed damage rotective sand cushion, and 1. Where a liner is used over rock or other maters al that ma°to 2" size NOTES• liner, the liner shall be laid on a 4" p ade of 3~d covered by a stmrlar cu `avel bed shall be m a Permeable material, sha•IfVotal co 2, The crushed stone or g r ravel bed. hard stone. formed by 3. Sand co4umth~ough the crushed stone orea. Water completely 15°!0 of the beea to drain storm ur oses; final construction umn area shall be 16 fo 4. The surface shall be mounded or s oP isfor illustrative p P 5, The a~oshall be1s~gte specific. desig 1~ a r ~~ I' c' 1` t:~ i+ IF 1 r. °_. n ., I' Vl rl N °n w G' '~ This agency hereby certifies that the rule ea adopted has been reviewed by legal counsel and found to be a valid exercise of the agency's legal authority. IaeueO In Austin, Texas, on June 30, 1987. TRD~8705471 Robert A. MacLean Deputy Commissioner Professional Service Texas Department of " Health Effxtlve dale: July 23, 7987 Proposal publication date: January t3, 7987 For further Infortnatlon, please call (512) 4587238. ~ ~ NOTE: EFFECTIVE DATE FOR THESE RULES IS JANUARY 1, 1988, CONTRARY TO DATE STATED IN THIS REGISTER" 3Z ; Adopted Rules July 10. /987 /2 Te.rHeK 1:Si