§ 51.02  DEFINITIONS.

     For the purpose of this chapter, the following definitions shall apply unless the context clearly indicates or requires a different meaning.

     ABS.  Acrylonitrile-butadiene-styrene.

     APPROVED SEPTIC SYSTEM.  A permitted septic system installed in accordance with state regulation and county ordinance which has been inspected and signed by the Health Officer or his or her designee.

     ASTM.  American Society for Testing and Materials.

     BARRIER MATERIAL.  A geotextile fabric with an effective opening size no smaller than 0.20 millimeters and no larger than 0.85 millimeters.

     BOARD OF HEALTH.  The Howard County Board of Health.

     COUNTY.  Howard County, Indiana.

     DISTRIBUTION BOX.  A structure designed to distribute effluent by gravity from a septic tank equally into the pipes of an absorption system connected thereto.

     DOSING TANK.  A concrete tank used in series behind a septic tank used to store liquids in amounts equivalent to the amount to be handled by the absorption field.  The dosing chamber is served by a properly sized pump which will “dose” the effluent to the absorption field.

     DRAINAGEWAY.  The channel portion of the landscape in which surface water or rainwater runoff gathers intermittently to flow to a lower elevation.

     DWELLING.  Any house or place used or intended to be used as a place of seasonal or permanent human habitation or for sleeping for one or two families.

     FILL.  Soil transported and deposited by man as well as soil recently transported and deposited by natural erosion forces.  Fill is evidenced by one or more of the following:

         (1)   No soil horizons or indistinct soil horizons.

         (2)   Depositional stratification.

         (3)   Presence of a soil horizon which has been covered.

         (4)   Materials in a horizon such as cinders or construction debris.

         (5)   Position in the landscape.

     FOUNDATION DRAIN.  That portion of a residential drainage system provided to drain only ground water from outside of the foundation of the house or from under the basement floor.

     HEALTH OFFICER.  The Howard County Health Officer, his or her assistant, or his or her designees, having responsibility for the enforcement of this chapter.

                                                                          Sewer Regulations                                                                 7

LIMITING LAYER.  Any soil horizon with a loading rate less than 0.25 gallons per day per square foot, or greater than 0.75 gallons per day per square foot.

     LOADING RATE.  The allowable rate of application of septic tank effluent to the soil.  It is expressed in gallons per day per square foot.

     NEW SEPTIC SYSTEM.  Any system proposed for new dwelling construction.

     OWNER.  The owner of a dwelling or his or her agent.

     PERSON.  The term includes any individual, partnership, copartnership, firm, company, corpora-tion, association, trust, estate or any other legal entity, including but not limited to its or their successors or assigns or agents.

     PVC.  Polyvinyl chloride.

     REPAIR.  The term includes any alteration, addition or replacement of any portion of an existing septic system.

     RESIDENTIAL DRAIN.  The horizontal piping in a house drainage system which receives the discharge from soil, waste and drainage pipes inside the walls of the house and conveys the same to the residential sewer.

     RESIDENTIAL SEWAGE DISPOSAL SYSTEM.  All equipment and devices necessary for proper conduction, collection, storage, treatment and on-site disposal of sewage from a one or two family dwelling.  Included within but not limited to the scope of this definition are residential sewers, septic tanks, soil absorption systems, temporary sewage holding tanks and sanitary vault privies.

     RESIDENTIAL SEWAGE DISPOSAL SYSTEM FAILURE.  A residential sewage disposal system which exhibits one or more of the following, and is therefore considered a health hazard:

         (1)   The system refuses to accept sewage at the rate of design application, thereby interfering with the normal use of residential plumbing fixtures.

         (2)   Effluent discharge exceeds the absorptive capacity of the soil, resulting in ponding, seepage or other discharge of the effluent to the ground surface or surface waters.

         (3)   Effluent is discharged from the system causing contamination of a potable water supply, ground water or surface waters.

     SANITARY SEWER.  A sewer or system of sewers which convey sewage away from the lot on which it originates to a waste water treatment facility owned and operated by an incorporated city or town, conservancy district, regional sewer district or private utility.

     SDR.  Means standard dimension ratio.

     SEPTIC TANK.  A water-tight structure into which sewage is discharged for settling and solids digestion.

     SEWAGE.  All water-carried waste derived from ordinary living processes.

     SLOPING SITE.  Any portion of the proposed area designated for the septic system with greater than a 2% slope.

     SLUDGE.  The digested or partially digested solid material accumulated in a septic tank.

     SOIL ABSORPTION.  A process which utilizes the soil to treat and dispose of effluent from a septic tank.

     SOIL ABSORPTION SYSTEM.  Pipes laid level in a system of trenches or elevated beds into which the effluent from the septic tank is discharged for soil absorption.  The term may also be referred to as residential septic system, residential sewage disposal system, absorption system or leach field

                                                                Howard County - Public Works

 

SOIL HORIZON.  A layer of soil or soil material approximately parallel to the land surface and differing from adjacent genetically related layers in physical, chemical and biological properties or characteristics such as color, structure, texture, consistency, kinds and numbers of organisms present, and degree of acidity or alkalinity.

     SOIL MAPPING SYMBOLS.  Those symbols used by the Soil Conservation Service in mapping the soil series in the county based on the limitations of the soil described as “slight, moderate, and severe.”

     SOIL PROFILE ANALYSIS.  The observation and evaluation of the physical characteristics of the soil horizons or layers to a depth of at least five feet or, if shallower, to a layer which cannot be readily penetrated.

     SOIL SCIENTIST.  A registered professional in the field of soil science holding a baccalaureate degree with a major in agronomy, soils or a closely related field of science who is proficient in the application of the principles of pedology to soil classification, investigation, education and consultation and on the effect of measured, observed and inferred soil properties and their use.

     UNSANITARY CONDITION.  Any condition that may transmit, generate or promote disease.

     WATER TABLE and SEASONAL HIGH WATER TABLE.  Means the upper surface of the ground water or that level below which the soil is saturated with water.

(BCC Ord. 1993‑34, passed 11‑1‑93)

§ 51.04  PERMITS REQUIRED; REFUSAL OR REVOCATION OF PERMITS.

     (A)   Residential sewage disposal systems.

         (1)   The owner or agent of the owner shall obtain a written permit, signed by the Health Officer, for construction of a residential sewage disposal system prior to:

                                                                   Sewer Regulations                                                                 9

              (a)   Construction of a residence which will not be connected to a sanitary sewerage system.

              (b)   Any replacement, reconstruction of, expansion or remodeling of a residence which may increase the number of bedrooms.

              (c)   Any addition to, alteration of or repair of an existing residential sewage disposal system.

         (2)   The application for such a permit shall be made on a form provided by the Health Department and shall contain the following information:  soil profile analysis, lot dimensions, number of bedrooms, location to drainage outlets and any other information deemed necessary by the Health Officer.  Plans shall be to a suitable scale of one inch equal to ten feet and shall indicate the location of all existing and proposed buildings, property lines, septic tank and absorption fields, tile and open drains and wells on the property to be developed and on those properties immediately adjacent to it.  Sufficient existing and proposed elevations shall be also be provided.

         (3)   If it is determined that the proposed system design does not meet the minimum requirements of this rule, the permit shall be denied and the owner shall be notified in writing of the basis for denial, and the notification shall state the appropriate procedure for registering any such appeal.

         (4)   The permittee shall notify the Health Officer or his or her designee when the work is ready for final inspection and at least 48 hours or two working days before any subsurface portions are to be covered.  Soil absorption systems that require more than one inspection due to improper installation or improper scheduling, and the like, will be required to pay an additional fee for each additional inspection necessary.

         (5)   The Board of Health, its agent, or the Health Officer or his or her agent shall be permitted to enter upon all properties at the proper time for purposes of inspection, observation, measurement, sampling and testing necessary to assure compliance with this rule.

         (6)   The installation of the permitted soil absorption system must be completed to the exact design specifications.  No portion of the permitted design is to be altered without first consulting with the Board of Health.  Any alteration of an approved and permitted soil absorption system design without the consultation and issuance of an amended permit will result in an unapproved and non-compliant system.  No certificate of occupancy will be granted for any construction or change of use until such time as the sewage disposal system has been certified approved.

     (B)   Commercial permit.  The owner or agent of the owner shall obtain a written permit, signed by the Health Officer, for construction of a commercial sewage disposal system prior to construction of an establishment classified and rated as a business.

         (1)   The application for such a permit shall be made on a form provided by the Howard County Health Department specifically for commercial sites.

         (2)   The application shall include a copy of the permit issued from the State Department of Health, a copy of the soil profile analysis, and a blue print copy of the design submitted to the State Department of Health.  The information shall include but not be limited to all pertinent information covered in division (A) of this section.

     (C)  Refusal or revocation of permits.

         (1)   If an applicant is refused a permit, the Board of Health shall, upon request, afford the applicants the opportunity for a fair hearing.

         (2)   The Health Department may revoke a permit which had been issued for construction of a residential sewage disposal system if it finds that the owner of the permit has failed to comply with this rule.  Upon such notice, the Board of Health shall upon request afford the applicant the opportunity for a fair hearing.

(BCC Ord. 1993‑34, passed 11‑1‑93)  Penalty, see § 51.99

§ 51.05  FEE SCHEDULE.

                                                                  Howard County - Public Works

The fee schedule for this chapter is as follows:

     Septic Installers License................... $100 annual

     Septic Permit (residential)......... ...... $50

     Septic Permit (commercial)............... $50

     On-Site Evaluation........................... $25

     Additional Septic Inspection............. $25*

 * Septic inspections for lots are provided in the amount of one per lot, and are scheduled by the applicant.  In the event that the site needs more than one inspection due to improper planning, non-compliant installation, and the like, there will be a charge for each additional inspection performed by a representative of the County Health Department.

(BCC Ord. 1993‑34, passed 11‑1‑93)

§ 51.21  CONNECTION TO EXISTING SYSTEM.

     Connection to an existing soil absorption system shall be permitted if the following conditions are met.

     (A)   The connection will not exceed the system design load based on the sizing requirements of this chapter.

     (B)   The existing system has not malfunctioned.

                           

     (C)  The existing system has been permitted and approved by the Health Officer, and the applicant has possession of record of the permitted and approved system which shows all system dimensions.

     (D)  If the existing system shall fail, there is sufficient space for system replacement.

     (E)   In the event that a system enlargement is proposed, the enlargement must bring existing system into compliance with the minimum standards of this chapter.

(BCC Ord. 1993‑34, passed 11‑1‑93)  Penalty, see § 51.99

§ 51.23  LOCATION AND SIZE.

     (A)   The residential sewage disposal system shall be located at least 50 feet from any water supply well or subsurface pump suction line.   Sewers constructed of water works grade ductile iron pipe with mechanical joints or PVC pressure sewer pipe with an SDR rating of 26 or less, having mechanical or compression gasket joints, may be located within the 50 foot distance.  In no case, however, shall sewers be located closer than 20 feet to dug and bored water supply wells nor closer than 10 feet to drilled and driven water supply wells or subsurface pump suction lines.

     (B)   Water lines and sewers shall not be laid in the same trench.  A horizontal separation of 10 feet shall be maintained between water lines and sewers.  Where crossing are necessary, a minimum of 18 inches vertical clearance must be maintained.  When it is impossible to maintain proper horizontal and vertical separation, the sewer shall be constructed of ductile iron pipe with mechanical joints or PVC pressure sewer pipe with an SDR rating of 26 or less, having mechanical or compression gasket joints within 10 feet of the water line; such sewer shall be pressure tested to assure water-tightness prior to back filling.

     (C)  The residential sewer shall be a minimum of four inches in diameter.  Four-inch sewers shall be installed with a positive slope of not less than 4 inches in 25 feet and not more than 36 inches in 25 feet.  Six-inch sewers if utilized shall be installed with a positive slope of not less than 2 inches in 25 feet and not more than 36 inches in 25 feet.

(BCC Ord. 1993‑34, passed 11‑1‑93)  Penalty, see § 51.99

§ 51.24  SEPTIC TANKS; CONSTRUCTION REQUIREMENTS.

     (A)   General requirements.

         (1)   All septic tanks, dosing tanks, lift stations and soil absorption systems shall be located in accordance with Table I, as set forth in Appendix A.

         (2)   Septic tanks shall be water-tight and constructed of durable material such as concrete, fiberglass or plastic and shall be protected from corrosion.

     (B)   Capacity.

         (1)   Every septic tank shall have a minimum capacity below the water line as specified in Table II, as set forth in Appendix A.

         (2)   Minimum water depth in any compartment shall be 30 inches.

         (3)   Maximum depth of water for calculating capacity of tank shall not exceed 6½ feet.

         (4)   All septic tank effluent including effluent from tanks fitted with aeration units for aerobic digestion shall discharge into a soil absorption system.

     (C)  Construction details.

         (1)   The septic tank inlet baffle or sanitary tee shall extend six inches below the liquid level and at least to the top of the inlet sewer.

         (2)   The septic tank outlet baffle or sanitary tee, and baffles or submerged pipes between compartment, shall extend below the liquid level a distance of 0.4 times the tank liquid depth.  A gas deflection baffle shall be provided below the outlet of the tank.  This baffle shall be constructed of durable materials not subject to corrosion or decay and shall be configured to deflect rising gas bubbles away from the outlet structure and toward the interior of the tank.

         (3)   There shall be at least one inch clear space between the under side of the septic tank cover and the top of the inlet and outlet baffles or tees.

         (4)   Scum storage capacity (space between the liquid level and the top of the outlet baffle) shall be not less than 15% of the total liquid depth of the septic tank.

         (5)   The septic tank inlet baffle shall not be more than 12 inches nor less than 8 inches from the inside of the inlet end of the tank.  The outlet baffle shall not be more than 6 inches nor less than 4 inches from the outlet end of the tank.  Baffles shall be constructed of durable materials not subject to corrosion or decay.

(6)   The bottom of the inlet to the septic tank or the first compartment receiving the flow shall not be less than three inches above the flow line of the outlet from that compartment.

         (7)   Access manholes at least eight inches in diameter extending to the ground surface and fitted with safely secured gas-tight covers shall be provided for each septic tank or compartment.

         (8)   Access for inspection shall be provided in the top of the septic tank above the inlet and outlet baffles of each tank and compartment.

         (9)   Reinforced or un-reinforced concrete septic tanks wherein the concrete has a compressive strength of less than 4,000 pounds per square inch shall have walls of 4 inches or greater in thickness.

         (10)     Reinforced concrete septic tanks wherein the concrete has a compressive strength of 4,000 pounds per square inch or greater shall have walls of 2½ inches or greater in thickness.

         (11)     Cast-in-place concrete septic tanks and concrete block tanks are not acceptable.

         (12)     Septic tank bottoms shall conform to the specifications set forth for septic tank walls.

         (13)     Concrete septic tank tops shall be a minimum of four inches in thickness and reinforced with ¼-inch reinforcing rods in a six inch grid or equivalent.

         (15)     All drain holes shall be plugged after the septic tank has been set.

         (16)     All septic tanks shall be installed level and the tank checked prior to covering to assure that it is level.

         (17)     Tanks fitted with aeration units for aerobic digestion shall conform to Standard 40 of the National Sanitation Foundation or to the standards of an equivalent testing laboratory and shall provide a minimum aerobic treatment capacity of 150 gallons per bedroom per day or 500 gallons per day, whichever is greater.

     (D)  Connecting pipes. 

         (1)   All inlet and outlet connections to the septic tank shall be sealed to the tank in a water-tight manner.

         (2)   All joints in the sewer connecting septic tanks in series shall be water-tight.

(BCC Ord. 1993‑34, passed 11‑1‑93)  Penalty, see § 51.99

 

§ 51.28  DOSING TANKS.

     (A)   Dosing tanks must be water-tight and constructed of durable material such as concrete, fiberglass or plastic and shall be protected from corrosion.

     (B)   Reinforced or un-reinforced concrete dosing tanks wherein the concrete has a compressive strength of less than 4,000 pounds per square inch shall have walls of 4-inch or greater thickness.    

§ 51.32  ON-SITE EVALUATIONS.

     (A)   Before issuance of any permit for construction of a residential sewage disposal system, new or repair, an on-site evaluation which shall include an evaluation of the soil must be performed.  System feasibility, location, selection and design shall be based on the site evaluation and information obtained from the direct soil profile analysis.  Properties of the soil at each site shall be determined using the guidelines set forth in the manuals of the SCS soil survey for Howard County.

     (B)   The County Health Department shall provide soil profile analysis for “new” construction of absorption systems for lots proposed to be located in soils mapped as “slight to moderate” for soil absorption systems based on the ratings provided by the Soil Conservation Service as listed in the Howard County Soil Survey.  The County Board of Health shall charge a fee for the service of providing soil profile analysis for both “new and repair” situations.

         (1)   The County Board of Health will provide soil profile analysis in the event of soil absorption system failure.

         (2)   The County Board of Health shall reserve the right in any situation to require the consultation of a certified professional soil scientist and/or registered professional engineer when deemed necessary.

     (C)  All “new” residential septic systems proposed for location in soils rated as “severe” by SCS shall be required to have soil profile analysis completed by a certified professional soil scientist.

         (1)   Those lots evaluated by professional soil scientists shall be interpreted by the County Board of Health.  All lots determined by the Board of Health to require above ground or below ground pressure distributed systems shall be required to have systems designed by a registered professional engineer, competent in the field of septic system design.  The County Board of Health may require the consultation of a registered professional engineer when deemed necessary.  Design engineers shall accompany the environmental health specialist inspection of such system and sign accompanying permit in approval or disapproval, along with the environmental health specialist completing the inspection.

         (2)   Lots requiring the consultation of a soil scientist that qualify for gravity feed, gravity feed flood dose, and gravity feed alternating field may be designed to the scale of one inch to ten feet by the property owner, licensed septic installer, or registered professional engineer.

     (D)  When direct soil profile analysis observations are made, soil profile information shall be recorded to a depth of at least five feet or until a layer is encountered which cannot be readily penetrated, whichever is shallower.

     (E)   The on-site evaluation shall be conducted before construction begins.  No construction on the residential sewage disposal system may take place if the residential sewage disposal system site is disturbed or altered after the on-site evaluation by the addition of fill material, (other than construction necessary for the residential sewage disposal system) or by cutting, scraping, compaction, or the removal of soil, until a new evaluation has been conducted and a modified permit has been issued.

     (F)   When any site limitations and soil information for the site has been determined, the owner is responsible for designing or having designed a residential sewage disposal system which addresses the demands of the site in accordance with this chapter, and which will meet the approval of the County Board of Health.

     (G)  The information needed to evaluate a site is the responsibility of the applicant and includes the following:

         (1)   Topographic information including the following:

             (a)   Slope and slope aspect.

             (b)   Surface drainage characteristics and patters including swales, ditches and streams.

             (c)   Location, distance and depth of perimeter drainage outlets.

             (d)   Proposed or existing location of house and well.

             (e)   Location of other major features or structures.

             (f)    Topographic position of site.

             (g)   Copies of the soil profile analysis when completed by a professional soil scientist.

 

(2)   Soil characteristics on soil profiles must provide the following:

             (a)   Approximate depths of soil horizons.

             (b)   Soil color, structure, texture and consistency at each horizon.

             (c)   Depth to any layer which has a loading rate greater than 0.75 gallons per day per square foot.

             (d)   Depth to seasonal high ground water table as indicated by soil wetness characteristics.

             (e)   Depth to any layer which has a loading rate less than 0.25 gallons per day per square foot.

             (f)    Soil effervescence at each horizon.

             (g)   Presence or absence of roots.

         (H)   Soil absorption systems shall not be constructed in areas where surface drainage or run-off will have an adverse effect on the system unless the surface run-off can be effectively diverted around the system.

         (I)    Soil absorption systems shall not be constructed below the floodway elevation of any flood having a peak discharge equaled or exceeded by the average of once in any 100-year period.

         (J)   Soil absorption systems shall not be constructed in areas subject to ponding.

         (K)   Soil mapping symbols and ratings are established in Table IV, as set forth in Appendix A.

(BCC Ord. 1993‑34, passed 11‑1‑93)  Penalty, see § 51.99

§ 51.35  ELEVATED SYSTEM SELECTION CRITERIA.

 

(A)   Elevated sand mound systems may be constructed if the following site conditions are met:

     (1)   Sufficient area exists on the lot for an appropriately sized system.

          (2)   The site on which the system is to be built has a slope of 6% or less.

          (3)   The topographic position of the site on which the system is to be built is convex, hill slope or flat.  If surface and subsurface drainage can be diverted around the site, a toe slope position can be utilized.

          (4)   There are no soil horizons within 20 inches from the ground surface which have a loading rate of less than 0.25 gallons per day per square foot as determined from Table VI, as set forth in Appendix A.

          (5)   There are no soil horizons within 20 inches from the ground surface which have a loading rate of more than 1.20 gallons per day per square foot as determined from Table VI, , as set forth in Appendix A, unless that hazard can be overcome through system design.

          (6)   Any seasonal high water table at the site of the proposed system can be lowered to 20 inches or more from the surface.

          (7)   There is at least 30 feet of dispersal area downslope of the downslope toe of the mound if the slope of the site on which the mound is to be built is 2% or less and if the loading rate of the soil in the dispersal area is not less than 0.5 gallons per day per square foot.  If the slope of the site on which the mound is to be built is greater than 2% or if the loading rate of the soil in the dispersal area has a loading rate of 0.3 gallons per day per square foot or less, at least 50 feet of dispersal area must be provided down slope of the downslope toe of the mound.  No obstruction to horizontal flow of water such as parking areas, building foundations, swimming pools or any other facility that would compact soil in the dispersal area may be placed in the dispersal area.

     (B)   Loading rates for above ground systems are established in Table VI, as set forth in Appendix A.

(BCC Ord. 1993‑34, passed 11‑1‑93)  Penalty, see § 51.99

§ 51.36  SUBSURFACE GRAVITY FEED TRICKLE FLOW SYSTEMS; CONSTRUCTION REQUIREMENTS.

     (A)   The minimum absorption area (in square feet) required for each gravity feed trickle flow subsurface soil absorption system shall be based on the following:

         (1)   The number of bedrooms and bedroom equivalents in the dwelling.

         (2)   The appropriate soil loading rate (in gallons per day per square foot) determined from Table V, as set forth in Appendix A.

         (3)   The vertical separation distance between the bottom of the proposed trench and any soil layer with a loading rate of less than 0.25 gallons per day per square foot.  The loading rate used for this computation shall be the loading rate of the most restrictive layer within 24 inches of the trench bottom.

         (4)   The absorption area shall be computed using the following formula:

                 Area =             150 gal. x # of bedrooms and bedroom equivalents

                                               loading rate in gpd/sq. ft.

         (5)   If the loading rate determined from Table V, as set forth in Appendix A, is 0.25 gallons per day per square foot or 0.30 gallons per day per square foot, the system may be reduced in size from the absorption area determined in division (A)(4) by 0.9% for each inch over 24 inches to a maximum of 60 inches between the trench bottom and a layer with a loading rate of less than 0.25 gallons per day per square foot.

  The new absorption area shall then be computed using the following formula: 

 New Absorption Area =

             A.A. - [A.A. x 0.009 (D.L. - D.T. - 24)]

             A.A. =     Absorption Area determined in division (A)(4)

        D.L. =     Depth in inches from the ground surface to a layer with a loading rate of 0.25 gallons per day per square foot.

        D.T. =     Depth in inches from the ground surface to the proposed trench bottom.

 

Note: The value for the quantity (D.L. - D.T. - 24) may not exceed 36.  If a value of greater than 36 is obtained, then 36 must be used for the computations.

     (B)   All gravity feed trickle flow subsurface soil absorption systems shall be located in accordance with the separation distances shown in Table I, as set forth in Appendix A.  Gravity feed trickle flow subsurface soil absorption systems shall not be constructed where there exist horizons, layers or strata within 34 inches of the ground surface with a loading rate greater than 0.75 gallons per day per square foot as determined from Table V, as set forth in Appendix A.

     (C)  Soil absorption systems shall not be wholly or partly located in a drainage way subject to intermittent flooding.

     (D)  In order to provide equal flow distribution in gravity feed trickle flow subsurface soil absorption systems, each absorption trench must be individually connected to a distribution box by at least five feet of unperforated pipe which is laid with a gravel free back fill.  All absorption trenches served by a common distribution box must be constructed so that each square foot of the absorptive area served by the distribution box is loaded with an equal volume of effluent.  The distal ends on the distribution lines may not be manifolded together.

     (E)   Each trench and distribution line in a gravity feed trickle flow subsurface soil absorption system shall be uniformly level throughout its length.

     (F)   No single absorption trench in a gravity feed trickle flow subsurface soil absorption system shall exceed 100 feet in length.

     (G)  On sloping sites, absorption trenches of a gravity feed trickle flow soil absorption system shall be constructed along the contour.

     (H)   There shall be a minimum separation of 7½ feet on center between absorption field trenches.

     (I)    All gravity feed trickle flow subsurface soil absorption fields shall be designed to utilize trenches with a minimum width of 18 inches and a maximum trench width of 36 inches.

     (J)   The minimum depth from original grade to the bottom of a trench of a gravity feed trickle flow subsurface soil absorption system shall not be less than ten inches, and the maximum depth to the bottom of a trench of a gravity feed trickle flow subsurface soil absorption system shall not be more than 36 inches.

     (K)   Perforated pipe distribution lines in the absorption trench of a gravity feed trickle flow subsurface soil absorption system shall be completely surrounded by aggregate which meets the specifications in this chapter.  There shall be at least six inches of aggregate below the pipe and at least two inches of aggregate above the pipe.

     (L)   The aggregate used in a gravity feed trickle flow subsurface soil absorption system shall be covered with a geotextile fabric barrier which meets the minimum requirements of this chapter.

     (M)  A minimum of 12 inches of cover shall be provided over the aggregate in the trenches, any fill required to provide cover shall be crowned over the entire field to promote surface run-off.

     (N)   Subsurface soil absorption systems shall not be constructed in clayey soils during periods of wet weather when the soil is sufficiently wet at the depth of installation to exceed its plastic limit.  This includes those soils classified as sandy loam, silt loam, loam, clay loam, silty clay loam, sandy clay, silty clay and clay.   For the purpose of this chapter, the plastic limit of a soil shall be considered to have been exceeded when the soil can be rolled between the palms of the hands to produce threads _-inch in diameter without breaking or crumbling.

     (O)  Special caution shall be taken to prevent wheeled and tracked vehicles from compacting the area selected for placement of the absorption system before, during and after construction of the trenches,  especially during wet weather.  Precaution is especially important where clayey soils are involved.  This includes those soils classified as sandy loam, silt loam, loam, clay loam, silty clay loam, sandy clay, silty clay and clay.  Alteration of soil structure by movement of vehicles may be grounds for rejection of the site or the system.

     (P)   Excessive smearing of the usable absorption trench sidewalls or bottom during construction may result in irreversible damage to the soil infiltrative surface and may be grounds for rejection of the site or the system.

(BCC Ord. 1993‑34, passed 11‑1‑93)  Penalty, see § 51.99

§ 51.37  SUBSURFACE GRAVITY FEED FLOOD DOSED SYSTEMS.

     (A)   The minimum absorption area (in square feet) required for each gravity feed flood dosed subsurface soil absorption system shall be based on the following:

         (1)   The number of bedrooms and bedroom equivalents in the dwelling.

         (2)   The appropriate soil loading rate (in gallons per day per square foot) determined from Table V, as set forth in Appendix A.

         (3)   The vertical separation distance between the bottom of the proposed trench and any soil layer with a loading rate of less than 0.25 gallons per day per square foot.  The loading rate used for this computation shall be the loading rate of the most restrictive layer within 24 inches of the trench bottom.

         (4)   The absorption area shall be computed using the following formula: 

 

            Area =                 150 gal. x # of bedrooms and bedroom equivalents

                                               loading rate in gpd/sq. ft.

         (5)   If the loading rate determined from Table V, as set forth in Appendix A, is 0.25 gallons per day per square foot or 0.30 gallons per day per square foot, the system may be reduced in size from the absorption area determined in division (A)(4) by 0.9% for each inch over 24 inches to a maximum of 60 inches between the trench bottom and a layer with a loading rate of less than 0.25 gallons per day per square foot.  The new absorption area shall then be computed using the following formula: 

New Absorption Area =

                       A.A. - [A.A. x 0.009 (D.L. - D.T. - 24)]

                       A.A. =     Absorption Area determined in division (A)(4)

                  D.L. =     Depth in inches from the ground surface to a layer with a loading rate of 0.25 gallons per day per square foot.

                  D.T. =     Depth in inches from the ground surface to the proposed trench bottom.

 Note: The value for the quantity (D.L. - D.T. - 24) may not exceed 36.  If a value of greater than 36 is obtained, then 36 must be used for the computations.

     (B)   All gravity feed flood dosed absorption systems shall be located in accordance with the separation distances shown in Table I, as set forth in Appendix A.  Gravity feed trickle flow subsurface soil absorption systems shall not be constructed where there exist horizons, layers or strata within 34 inches of the ground surface with a loading rate greater than 0.75 gallons per day per square foot as determined from Table V, as set forth in Appendix A.

     (C)  Gravity feed flood dosed absorption systems shall not be wholly or partly located in a drainage way subject to intermittent flooding.

     (D)  In order to provide equal flow distribution in gravity feed flood dosed subsurface soil absorption systems, each absorption trench must be individually connected to a distribution box by at least five feet of unperforated pipe which is laid with a gravel free back fill.  All absorption trenches served by a common distribution box must be constructed so that each square foot of the absorptive area served by the distribution box is loaded with an equal volume of effluent.  The distal ends on the distribution lines may not be manifolded together.

     (E)   Each trench and distribution line in a gravity feed flood dosed subsurface soil absorption system shall be uniformly level throughout its length.

     (F)   No single absorption trench in a gravity feed flood dosed subsurface soil absorption system shall exceed 100 feet in length.

     (G)  On sloping sites, absorption trenches of a gravity feed flood doses soil absorption system shall be constructed along the contour.

     (H)   There shall be a minimum separation of 7½ feet on center between absorption field trenches.

     (I)    All gravity feed flood dosed subsurface soil absorption fields shall be designed to utilize trenches with a minimum width of 18 inches and a maximum trench width of 36 inches.

     (J)   The minimum depth from original grade to the bottom of a trench of a gravity feed flood dosed subsurface soil absorption system shall not be less than 10 inches, and the maximum depth to the bottom of a trench of a gravity feed flood dosed subsurface soil absorption system shall not be more than 36 inches.

     (K)   Perforated pipe distribution lines in the absorption trench of a gravity feed flood dosed subsurface soil absorption system shall be completely surrounded by aggregate which meets the specifications in this chapter.  There shall be at least six inches of aggregate below the pipe and at least two inches of aggregate above the pipe.

     (L)   The aggregate used in a gravity feed flood dosed subsurface soil absorption system shall be covered with a geotextile fabric barrier which meets the minimum requirements of this chapter.

     (M)  A minimum of 12 inches of cover shall be provided over the aggregate in the trenches, and any fill required to provide cover shall be crowned over the entire field to promote surface run-off.

     (N)   Subsurface soil absorption systems shall not be constructed in clayey soils during periods of wet weather when the soil is sufficiently wet at the depth of installation to exceed its plastic limit.  This includes those soils classified as sandy loam, silt loam, loam, clay loam, silty clay loam, sandy clay, silty clay and clay.   For the purpose of this chapter, the plastic limit of a soil shall be considered to have been exceeded when the soil can be rolled between the palms of the hands to produce threads _-inch in diameter without breaking or crumbling.

     (O)  Special caution shall be taken to prevent wheeled and tracked vehicles from compacting the area selected for placement of the absorption system before, during and after construction of the trenches, especially during wet weather.  Precaution is especially important where clayey soils are involved.  This includes those soils classified as sandy loam, silt loam, loam, clay loam, silty clay loam, sandy clay, silty clay and clay.  Alteration of soil structure by movement of vehicles may be grounds for rejection of the site or the system.

     (P)   Excessive smearing of the usable absorption trench sidewalls or bottom during construction may result in irreversible damage to the soil infiltrative surface and may be grounds for rejection of the site or the system.

     (Q)  Each trench and distribution line in a subsurface gravity feed flood dosed system shall be uniformly level throughout its length.

     (R)  When a subsurface gravity feed flood dosed soil absorption system is used the dosing pump shall be sized and its controls set to deliver the design daily flow in one dose each day.  Pump selection shall be based on manufacturers pump curves for the required discharge rate from Table VII, as set forth in Appendix A, at the total head imposed on the pump.  The total head for a subsurface soil absorption system using flood dosing shall be the elevation difference between the pump and the outlet in the distribution box in addition to the friction loss in the delivery pipe expressed in feet.

     (S)   The liquid holding capacity of a dosing tank must equal the design daily average waste water volume as further modified herein.  The delivery pipe from the pumping chamber to the absorption field must drain between doses.  If the delivery pipe drains to the absorption field, the dosing tank volume shall be the daily average waste water volume minus the volume contained in the delivery pipe.  If the delivery pipe drains back into the dosing tank, the dosing tank volume shall be the daily average waste water volume plus the volume contained in the delivery pipe.  Additional capacity must be provided to keep the dosing tank pump submerged at all times and to provide sufficient freeboard for a high water alarm.

     (T)   The distal end of the delivery pipe from the pumping chamber must be fitted with an elbow turned down, or else the distribution box must be baffled.

     (U)   The minimum inside diameter of the delivery pipe shall be one inch; the maximum inside diameter of the delivery pipe shall be four inches.

     (V)   Table VIII, as set forth in Appendix A, shall be used in determining friction losses in the delivery pipes and manifold when plastic pipe is used.

(BCC Ord. 1993‑34, passed 11‑1‑93)  Penalty, see § 51.99

§ 51.38  SUBSURFACE GRAVITY FEED TRICKLE FLOW ALTERNATING SYSTEMS.

     (A)   The minimum absorption area (in square feet) required for each gravity feed alternating field subsurface soil absorption system shall be based on the following:

          (1)   The number of bedrooms and bedroom equivalents in the dwelling.

          (2)   The appropriate soil loading rate (in gallons per day per square foot) determined from Table V, as set forth in Appendix A.

          (3)   The vertical separation distance between the bottom of the proposed trench and any soil layer with a loading rate of less than 0.25 gallons per day per square foot.  The loading used for this computation shall be the loading rate of the most restrictive layer within 24 inches of the trench bottom.

         (4)   The absorption area shall be computed using the following formula: 

 

                 Area =                                                150 gal. x # of bedrooms and bedroom equivalents

                                                            loading rate in gpd/sq. ft.

         (5)   If the loading rate determined from Table V, as set forth in Appendix A, is 0.25 gallons per day per square foot or 0.30 gallons per day per square foot, the system may be reduced in size from the absorption area determined in division (A)(4) by 0.9% for each inch over 24 inches to a maximum of 60 inches between the trench bottom and a layer with a loading rate of less than 0.25 gallons per day per square foot.  The new absorption area shall then be computed using the following formula: 

     New Absorption Area =

            A.A. - [A.A. x 0.009 (D.L. - D.T. - 24)]

            A.A. =     Absorption Area determined in division (A)(4)

       D.L. =     Depth in inches from the ground surface to a layer with a loading rate of 0.25 gallons per day per square foot.

       D.T. =     Depth in inches from the ground surface to the proposed trench bottom.

 Note: The value for the quantity (D.L. - D.T. - 24) may not exceed 36.  If a value of greater than 36 is obtained, then 36 must be used for the computations.

     (B)   All gravity feed alternating field subsurface soil absorption systems shall be located in accordance with the separation distances shown in Table I, as set forth in Appendix A.   Gravity feed alternating field subsurface soil absorption systems shall not be constructed where there exist horizons, layers or strata within 34 inches of the ground surface with a loading rate greater than 0.75 gallons per day per square foot as determined from Table V, as set forth in Appendix A.

    (C)  Soil absorption systems shall not be wholly or partly located in a drainage way subject to intermittent flooding.

    (D)  In order to provide equal flow distribution in gravity feed alternating field subsurface soil absorption systems, each absorption trench must be individually connected to a distribution box by at least five feet of unperforated pipe which is laid with a gravel free back fill.  All absorption trenches served by a common distribution box must be constructed so that each square foot of the absorptive area served by the distribution box is loaded with an equal volume of effluent.  The distal ends on the distribution lines may not be manifolded together.

     (E)   Each trench and distribution line in a gravity feed alternating field subsurface soil absorption system shall be uniformly level throughout its length.

     (F)   No single absorption trench in a gravity feed alternating field subsurface soil absorption system shall exceed 100 feet in length.

     (G)  On sloping sites, absorption trenches of a gravity feed alternating field soil absorption system shall be constructed along the contour.

     (H)   There shall be a minimum separation of 7½ feet on center between absorption field trenches.

     (I)    All gravity feed alternating field subsurface soil absorption fields shall be designed to utilize trenches with a minimum width of 18 inches and a maximum trench width of 36 inches.

     (J)   The minimum depth from original grade to the bottom of a trench of a gravity feed alternating field subsurface soil absorption system shall not be less than ten inches, and the maximum depth to the bottom of a trench of a gravity feed alternating field subsurface soil absorption system shall not be more than 36 inches.

     (K)   Perforated pipe distribution lines in the absorption trench of a gravity feed alternating field subsurface soil absorption system shall be completely surrounded by aggregate which meets the specifications in this chapter.  There shall be at least six inches of aggregate below the pipe and at least two inches of aggregate above the pipe.

     (L)   The aggregate used in a gravity feed alternating field subsurface soil absorption system shall be covered with a geotextile fabric barrier which meets the minimum requirements of this chapter.

    (M)  A minimum of 12 inches of comer shall be provided over the aggregate in the trenches, and any fill required to provide cover shall be crowned over the entire field to promote surface run-off.

     (N)   Subsurface soil absorption systems shall not be constructed in clayey soils during periods of wet weather when the soil is sufficiently wet at the depth of installation to exceed its plastic limit.  This includes those soils classified as sandy loam, silt loam, loam, clay loam, silty clay loam, sandy clay, silty clay and clay.  For the purpose of this chapter, the plastic limit of a soil shall be considered to have been exceeded when the soil can be rolled between the palms of the hands to produce threads _-inch in diameter without breaking or crumbling.

     (O)  Special caution shall be taken to prevent wheeled and tracked vehicles from  compacting the area selected for placement of the absorption system before, during and after construction of the trenches, especially during wet weather.  Precaution is especially important where clayey soils are involved.  This includes those soils classified as sandy loam, silt loam, loam, clay loam, silty clay loam, sandy clay, silty clay and clay.  Alteration of soil structure by movement of vehicles may be grounds for rejection of the site or the system.

     (P)   Excessive smearing of the usable absorption trench sidewalls or bottom during construction may result in irreversible damage to the soil infiltrative surface and may be grounds for rejection of the site or the system.   

§ 51.40  ELEVATED SAND MOUND SYSTEMS.

     (A)   The minimum basal area (in square feet) required for each elevated sand mound system shall be based on the following:

         (1)   The number of bedrooms and bedroom equivalents in the dwelling, and the appropriate soil loading rate (in gallons per day per square foot) determined from Table VI, as set forth in Appendix A.  The absorption area shall be computed using the formula:

  Absorption Area =            150 gal. x # of bedrooms and bedroom equivalents

                                      loading rate in gpd/sq. ft.

         The loading rate used for this computation shall be the loading rate of the most restrictive horizon within 20 inches of the soil surface.

(2)   On level sites, the basal area shall be the entire area under the mound excluding the end slope areas.  On sloping sites, the basal area shall be the area underneath and down slope of the aggregate bed.

        

(B)   All elevated sand mound systems shall be located in accordance with the separation distances shown in Table I, as set forth in Appendix A.  Elevated sand mound systems shall not be constructed where there exist horizons, layers or strata within 20 inches of the ground surface with a loading rate greater than 1.20 gallons per day per square foot as determined from Table V, as set forth in Appendix A, unless it can be overcome through system design.

     (C)  Elevated sand mound systems shall not be wholly or partly located in a drainage way subject to intermittent flooding.

     (D)  The elevated sand mound must be designed and constructed so that its longest axis is located along the contour.  The mound dimensions should be as long and narrow as possible for the site.

     (E)   The elevated sand mound site as well as the downslope absorption area shall be staked out and protected from vehicular traffic.

     (F)   Elevated sand mound systems shall not be constructed in clayey soils during periods of wet weather or when the soil is sufficiently wet at the depth of installation to exceed its plastic limit.  This includes those soils classified and sandy loam, silt loam, loam, clay loam, silty clay loam, sandy clay, silty clay and clay.  For the purpose of this rule, the plastic limit of a soil shall be considered to have been exceeded when the soil can be rolled between the palms of the hands to produce threads _-inch in diameter without breaking or crumbling.

     (G)  Excessive vegetation at the mound site must be cut and removed.  If present, trees must be cut off at ground level and the stumps left in place.

     (H)   The delivery line from the dosing tank to the manifold shall be installed prior to plowing the mound site.

     (I)    The area within the mound perimeter shall be plowed to a depth of seven to eight inches, parallel to the contour, with a moldboard or chisel plow.  If a moldboard plow is used, it shall have at least two bottoms (shares) and the soil shall be turned upslope.

     (J)   The sand fill shall meet the following conditions:

         (1)   Sand fill must be placed on the plowed area immediately after plowing the site.

         (2)   The sand utilized must be medium textured sand which meets the size criteria of Table XII, as set forth in Appendix A.

         (3)   The sand shall be placed on the plowed area starting from the upslope edge.  At least six inches of sand fill must be kept between the vehicle wheels or tracks and the native soil of the mound site at all times.

         (4)   There shall be a minimum of 12 inches of sand fill.  The surface of the sand fill shall be raked smooth to eliminate any ruts.  The toes of the fill shall be constructed to a minimum of a 3:1 slope.

     (K)   Aggregate shall be placed over the sand fill to form a bed.  The bottom of this aggregate bed shall be level.

     (L)   The aggregate bed shall be covered with a barrier material which meets the minimum requirements of this chapter.

     (M)  The total area of the aggregate bed (in square feet) shall be determined using the formula: 

                     Area =        150 gal. x # of bedrooms and bedroom equivalents

                                             1.2 gpd/sq. ft.

 

Aggregate beds shall not be less than four feet nor more than ten feet in width.  If more than one aggregate bed must be constructed, each bed shall provide equal absorptive area.

(N)   A pressure distribution network shall be used for elevated sand mound systems.  The pressure distribution system network shall be sized and its controls set to deliver four doses each day, each dose being approximately ¼ of the daily design flow, while maintaining an in-line residual pressure of 2.5 to 3 feet of head in the distribution line during pumping.

     (O)  The pressure distribution network must drain between doses.  If the delivery pipe drains to the distribution network, the dosing tank volume shall be the dose calculated using division (N), minus the volume contained in the delivery pipe.  If the delivery pipe drains back to the dosing tank, the dosing tank volume shall be the dose calculated using division (N), plus the volume contained in the delivery pipe.  Additional dosing tank capacity must be provided to keep the dosing tank pump submerged at all times to provide sufficient freeboard for a high water alarm.

     (P)   The minimum inside diameter of the delivery pipe shall be two inches and the maximum inside diameter of the delivery pipe shall be four inches.

     (Q)  Table VIII, as set forth in Appendix A, shall be used in determining friction losses in the delivery pipes and manifold when plastic is used.

     (R)  The delivery manifold piping diameter shall be determined from Table IX, as set forth in Appendix A.  The minimum inside diameter of the manifold shall be two inches and the maximum inside diameter of the manifold shall be four inches.

     (S)   The minimum inside diameter of the distribution pipes form the delivery manifold shall be one  inch and the maximum inside diameter of the distribution pipes shall be three inches.

     (T)   The holes in the lateral pipes shall be placed in the trenches facing down and all burrs shall be removed from the edges of the holes.

     (U)   The hole size in the laterals shall be ¼-inch.

     (V)   The end of each lateral shall be capped and a ¼-inch hole drilled in the upper half of the end cap.

     (W)  The system shall maintain an in-line residual pressure of 2.5 to 3 feet of head during pumping.

     (X)   All joints, including the end cap, shall withstand the pressures exerted on them.

     (Y)   The lateral lines in the absorption bed shall not be manifolded together.

     (Z)   The separation distance between laterals shall not be less than 24 inches nor more than 36 inches.

     (AA)       The holes on the bottom of the laterals shall be spaced 36 inches on center, with the first hole located 18 inches from the manifold.

     `(BB)       The elevated sand mound shall be designed and constructed to maintain at least a 3:1 slope on all sides.

        (CC)      The entire mound shall be covered with six inches of clayey textured soil with an additional six inches of topsoil covering the clayey textured soil for a total cover of 12 inches.

     (DD)      The elevated sand mound shall be seeded or sodded with grasses and legumes adapted to the area.  If the mound is seeded, the mound shall be protected by a cover of straw, burlap or some other material that will protect it against erosion until a vegetative cover develops.

(BCC Ord. 1993‑34, passed 11‑1‑93)  Penalty, see § 51.99