W. Va. Code R. § 64-47-6

Current through Register Vol. XLI, No. 50, December 13, 2024

Section 64-47-6 - Individual Sewage Systems

6.1. General. The design standards apply to the site requirements, design, construction, and maintenance of individual sewage treatment systems including septic tank soil absorption systems with standard soil absorption fields; serial distribution soil absorption fields; soil absorption beds; shallow soil absorption fields; mound systems; home aeration units; effluent disposal ponds; composting toilets; grey water disposal systems; holding tanks; privies; recycle systems; and any other systems that provide waste treatment and disposal for individual dwellings and commercial establishments.

6.1.a. When applying for approval for systems using soil absorption or on-site effluent disposal, an applicant shall submit to the Commissioner one copy of the completed application, the design data sheet, and the plan.

6.1.b. When applying for approval for systems using other methods of effluent disposal, an applicant shall submit to the Commissioner four copies of the completed application, the design data sheet, and the plan.

6.2. General Site Requirements.

6.2.a. The location of an individual sewage system shall not be in a poorly drained or filled area, or in any area where seasonal flooding occurs, without the prior written approval of the Commissioner. There may be exceptions if the construction of the fill area has been in accordance with directions of the Commissioner, or if an applicant provided evidence to the Commissioner that the fill area is suitable and of acceptable composition.

6.2.b. No part of an individual sewage system location shall be within 10 feet of a building, foundation, or property line.

6.2.c. No part of an individual sewage system location shall be within 25 feet of a public water supply line, or within 10 feet of a private water supply line.

6.2.d. The Commissioner shall determine the distance between a septic tank, home aeration unit, vault privy, or other sewage tank, and a public water system well or water supply.

6.2.e. The location of a septic tank, home aeration unit, vault privy, or other sewage tank shall be at least 50 feet from a private water well or groundwater supply.

6.2.f. The location of absorption fields, serial distribution systems, absorption beds, mound systems, and other soil absorption systems shall comply with the distances contained in Table 64-47-K at the end of this rule.

6.2.g. Roof drains, foundation drains, sump pumps, surface drains, or similar drains shall not connect to an individual sewage system.

6.2.h. The location of a septic tank or other treatment unit or disposal field shall not be under area to be paved, parking lots, driving surfaces, or any type of structure.

6.2.i. There shall be a minimum of three feet between any portion of a standard soil absorption system and seasonal groundwater bedrock, and any other impermeable layer.

6.2.j. There shall be no standard septic tank soil absorption system installed in soils where percolation test results show an average percolation time of less than five minutes per inch.

6.3. Site Evaluation.

6.3.a. The evaluation of a site for the installation of a soil absorption system, including absorption fields, serial systems, absorption beds, and others, shall include but not be limited to, percolation test results and evaluation of soils in a six-foot excavation. Percolation tests shall be performed according to the following:

6.3.a.1. A minimum of four test holes shall be placed at equal distances over the entire absorption field site. If the results of the tests are reasonably close, it shall be considered an average test result. If the tests results show extreme variations, it may be considered necessary to relocate the field in a more suitable area;

6.3.a.2. Holes shall be bored to the depth of the proposed soil absorption field from six to eight inches in diameter at the site where the installation of the soil-absorption field is to take place;

6.3.a.3. The bottom and sides of the hole shall be scratched with a sharp pointed instrument or wire brush to remove any smeared soil surfaces that interfere with the absorption of water into the soil;

6.3.a.4. The loose dirt shall be removed from the bottom of the test holes and two inches of gravel shall be placed into the holes to prevent sealing;

6.3.a.5. A nail or a marked measuring device shall be placed in the wall of each hole exactly six inches above the level of the gravel;

6.3.a.6. The test hole shall be completely filled with water to ground level and maintained to a depth of at least 12 inches for a minimum period of four hours before beginning the percolation rate measurement.

6.3.b. Percolation Rate Measurement. After completing the requirements in paragraphs 6.3.a.1. through 6.3.a.6., the water depth shall be adjusted in the holes to the six- inch level. Determine how many minutes it takes for all of the water to absorb into the soil. The resulting time in minutes, divided by six, shall be the rate of fall or absorption per inch.

6.3.b.1. The average rate of fall for all test holes shall be determined by adding the rate of fall for each test hole together and dividing by the number of test holes. This figure is the average rate of fall per inch. See Table 64-47-L at the end of this rule.

6.3.b.2. If desired, an applicant may use an alternate test, if approved by the local health department.

6.3.b.3. Observation Hole. A hole shall be excavated six feet deep in the center of the proposed soil absorption system area to evaluate the soil depth to bedrock and the seasonal water table. If slopes at the proposed site exceed 15%, the excavated observation hole shall be placed at the location of the lowest proposed trench of the system. Additional observation holes may be required when there are extreme variations in soil or geology in the test area.

6.3.b.4. Six feet deep slit trenches of a specified length may be required in limestone geology to determine depth to bedrock.

6.4. Septic Tanks.

6.4.a. Liquid capacities for tanks serving single-family dwellings shall be in accordance with the following:

6.4.a.1. For four or fewer bedrooms, the minimum tank capacity shall be 1,000 gallons; and

6.4.a.2. For each additional bedroom, the minimum tank capacity shall be 250 gallons per bedroom.

6.4.b. When using a dual compartment tank or dual tanks, the volume ratio of the first compartment or tank to the second compartment or tank shall approximate 2-to-1. In a dual compartment tank, the connection between compartments shall be an elbow with a minimum diameter of four inches, placed so that the invert at the partition is approximately 16 inches below the liquid level.

6.4.c. The construction of septic tanks may be of reinforced concrete, fiberglass or other watertight and durable materials approved by the Commissioner. All tanks shall meet the general requirements of subdivision 6.4.g. of this rule, regardless of construction material. Septic tank construction shall comply with the following:

6.4.c.1. Precast Concrete Septic Tanks. Concrete used shall consist of at least six bags of cement per yard of concrete mix or the equivalent, with a minimum compressive strength of 4,000 pounds per square inch based on a 28-day compression test. Reinforcement shall be at least six inches by six inches mesh number 10 welded wire fabric or the equivalent. Aggregate used in the concrete shall be no larger than one inch in size. There shall be vibrated concrete to minimize honey-combing. The sidewalls of the tanks shall be at least 2.5 inches in thickness. The top and bottom shall have a minimum thickness of four inches.

6.4.d. The manufacturers of concrete septic tanks shall obtain approval from the Commissioner for the construction of and compliance with the Design Standards.

6.4.e. Metal Septic Tanks. Metal septic tanks shall not be approved due to their potential to leak into ground water.

6.4.f. Plastic and Fiberglass Tanks. The Commissioner shall approve plastic and fiberglass tanks.

6.4.g. General requirements for tanks shall be as follows:

6.4.g.1. The invert of the inlet pipe shall be a minimum of two inches above the invert of the outlet pipe.

6.4.g.2. Inlets and outlets shall be a minimum of four inches in diameter and equipped with a flexible watertight seal.

6.4.g.3. The inlet shall equip a cast-in-place or inserted baffle or a sanitary tee. The inlet baffle or sanitary tee shall extend to a minimum depth of six inches, but to no more than 20% of the liquid depth.

6.4.g.4. The outlet shall equip a cast-in-place or inserted baffle or sanitary tee. The effluent baffle shall extend to at least 35% of the liquid depth, but to no more than 40% of the liquid depth.

6.4.g.5. The top of the inlet and outlet baffles or tees shall extend at least six inches above the flow line.

6.4.g.6. Minimum liquid depth shall be 30 inches.

6.4.g.7. There shall be a minimum of nine inches clearance above the liquid level.

6.4.g.8. The top of the tank, above the outlet, shall have embossing, imprinting, stenciling or other form of marking in an indelible and legible manner with the manufacturer's name, the liquid capacity and date of manufacture.

6.4.g.9. Access. There shall be adequate access to each compartment of the tank for inspection and cleaning. Both the inlet and outlet devices shall be accessible. When installing a septic tank at a depth greater than 12 inches below grade, it shall be required to install an extended manhole riser to within 12 inches of final grade.

6.4.g.10. All septic tanks shall have a four-inch gas tight inspection port that extends to the surface of the ground to measure sludge and scum accumulations.

6.5. The Standard Soil Absorption System.

6.5.a. The pipe for gravity distribution systems shall have a minimum diameter of four inches. Pressure distribution systems may use smaller size pipe.

6.5.b. Pipe used in the construction of soil absorption fields shall conform to the ASTM Standards for wastewater piping. This includes, but is not limited to:

6.5.c. Plastic pipe ASTM - D 2729, D 2852, D 3350, D 2751, D 2836, D 3033, D 3034, D 3298, F 789.

6.5.d. The septic tank inlet and outlet piping shall be schedule 40 or the equivalent. This pipe shall span the tank hole excavation and rest on a minimum of two feet of undisturbed soil.

6.5.e. Perforated pipe used in the construction of soil absorption systems shall have a minimum of two rows of downward facing holes approximately 90 degrees apart.

6.5.f. Aggregate used in the construction of a soil absorption field shall be washed gravel, crushed stone, or slag, 0.5 to 2.5 inches in size, with a hardness of three on the Mohs scale of hardness. The field test for hardness is that the aggregate shall scratch a copper penny without leaving a residue.

6.5.g. The installation of gravel-less soil absorption systems shall be in accordance with manufacturers' specifications as approved by the Commissioner.

6.5.h. The construction of the standard soil absorption field with either level or sloping topography shall be in accordance with the following specifications:

6.5.h.1. The trenches shall be one to three feet wide with a maximum depth of 36 inches and a minimum depth of 18 inches.

6.5.h.2. If distribution lines of greater than 100 feet are necessary, the connection of the inlet line shall be so that the lengths on either side of the connection shall not exceed 100 feet each. Absorption fields dosed by a pump or dosing siphon may utilize trenches of greater length, if reviewed and approved by the Commissioner.

6.5.h.3. There shall be a minimum of six inches of aggregate placed in the bottom of the trench beneath the pipe, and a minimum of two inches placed above the pipe.

6.5.h.4. The construction of the bottom of each trench and its distribution line shall be level. The construction of trenches shall be consistent with the topography and in such a manner so as to minimize the compaction or smearing of the sides and bottoms. Construction of the trenches shall not take place if the soil is so wet that it forms a "wire" instead of breaking apart when rolled between the hands. Construction shall not take place during rain or inclement weather that may interfere with or preclude correct construction procedures.

6.5.h.5. The surface of the aggregate shall have a cover of a minimum of three inches of straw or hay, or one layer of untreated building paper or filter fabric prior to backfilling.

6.5.h.6. There shall be a minimum of six feet of undisturbed earth between the sidewalls of each trench. Additional separation may be a requirement in areas of severe topography and poor soil characteristics to avoid interaction between the trenches.

6.5.h.7. The design of soil absorption fields constructed in flat areas shall be to provide a closed continuous system or closed-circuit design.

6.5.h.8. Performing the backfilling of the absorption field shall be in such a manner as to minimize compaction. There shall be a mound of backfill over the system to allow for settling and to promote run-off from the system. There shall be no grading to the absorption field construction area after backfilling. There shall be no backfilling if the ground is frozen.

6.5.h.9. The sewer line from the structure to the septic tank shall lay on a grade of not less than 0.125 of an inch per foot (1%).

6.5.h.10. The installation of the absorption field shall be so that the invert of the absorption field piping is a minimum of eight inches lower than the invert of the sewage tank outlet.

6.5.h.11. The construction of the standard soil absorption field in areas of sloping topography shall be in accordance with the following specifications:

6.5.h.11.A. Soil absorption fields constructed on sloping ground shall use a serial distribution system. This rule recommends the use of drop boxes;

6.5.h.11.B. The construction of soil absorption systems shall not be on ground with a slope in excess of 25%;

6.5.h.11.C. The bottom of each trench and its distribution line shall be level;

6.5.h.11.D. There shall be a minimum of six inches of ground cover over the gravel fill in each trench; and

6.5.h.11.E. The absorption trenches shall follow the approximate ground surface contours to minimize variation in trench depth.

6.5.h.12. Adjacent trenches shall connect with a relief line, cross over, or drop box arrangement in such a manner that each trench is completely filled with septic tank effluent to the full depth of the gravel before effluent flows to succeeding trenches. The construction of the relief line, cross-over, or drop box arrangement shall incorporate the following requirements:

6.5.h.12.A. The relief line or crossover shall be a solid four-inch sewer line with tight joints and with direct connection to the distribution lines or a drop box installation.

6.5.h.12.B. The construction of relief lines, cross-overs, and drop boxes shall not be in any location or manner where they shall be subject to damage during or following construction. An applicant shall mark the location of these relief lines, cross-overs, or drop boxes prior to backfilling to avoid damage from heavy equipment. The line shall rest on undisturbed earth with care given to carefully tamping the backfill.

6.5.h.12.C. The trench for the relief pipe or cross-over shall be no deeper than the top of the gravel of the trenches being connected. The line shall rest on undisturbed earth with care given to carefully tamping the backfill. An applicant shall exercise care in construction of the relief or cross-over line to ensure that an undisturbed block of earth remains between the trenches.

6.5.h.12.D. The invert of the overflow pipe in the first relief or cross-over line should be at least two inches lower than the invert of the septic tank outlet.

6.5.i. When servicing a structure other than a single-family dwelling, there shall be a reservation of land for the construction of two standard soil-absorptions fields, each of adequate size to serve the proposed structure.

6.5.j. If the soil absorption field is greater than 1,500 square feet in area, a siphon chamber or pump chamber may be required by the Commissioner to ensure even distribution of effluent.

6.5.k. Absorption fields over 3,000 square feet in total area shall include some form of dosing.

6.5.l. When a total field area over 5,000 square feet is necessary, the field shall be split into two or more fields of approximately equal size.

6.6. Absorption Beds.

6.6.a. The construction of absorption beds shall only be when topography or space limitations prevent installation of a standard absorption field.

6.6.b. The size of absorption beds shall be to provide an area 30% greater than that calculated for a standard absorption field to make up for sidewall loss.

6.6.c. The installation of the piping distribution network within the bed shall be in such a manner that the location of the pipes are 18 to 36 inches from the sides of the bed with a minimum of three feet between pipes and a maximum of six feet between pipes in a continuous or closed-circuit design. Construction of the bed shall be in accordance with the general design and construction requirements of the standard absorption field.

6.6.d. Maximum depth of an absorption bed shall be 36 inches, minimum depth shall be 18 inches.

6.7. Dual Soil Absorption Fields.

6.7.a. Use of dual absorption fields may receive approval if percolation rates are between 60 minutes and 90 minutes per inch.

6.7.b. Area reserved for absorption shall provide sufficient area for the replacement of dual soil absorption fields.

6.7.c. Construction of the dual absorption fields shall be in accordance with the dosing requirements of the standard soil absorption system, with a junction box or valving arrangement to provide for alternation of the fields. The size of each of the fields shall be in accordance with the percolation test results. Both fields shall be of the maximum sizing required for a 60 minutes per inch rate.

6.8. Shallow and Elevated Soil Absorption Systems.

6.8.a. Due to the shallowness of many West Virginia soils, a soil absorption system shall often have to be shallow, or the elevation shall be above the original ground surface to maintain the minimum distance above the seasonal high-water table, rock table, or impermeable soil layer. The construction of a shallow or elevated system is permissible where there is a suitable layer of soil, sufficient room, and the natural slope is not excessive. Shallow and elevated soil absorption systems presently approved for use are shallow fields, shallow beds, elevated fields, and unique systems designed for specific situations. Shallow systems are similar to the standard absorption field and they may receive consideration for new residences.

6.8.b. Use of shallow and elevated systems using gravity distribution may receive approval under conditions where pervious rock table, an impermeable layer of any type, or seasonal water table is less than 4.5 feet of the ground surface, on either level topography or sites of up to approximately 15% slope. When additional treatment precedes shallow or elevated fields, or designed as low-pressure distribution systems, the Commissioner may waive the separation distance to an impermeable layer, or seasonal water table from three feet to two feet. Due to a potential for groundwater contamination, the depth to pervious rock table shall not be less than three feet from any portion of the soil absorption system. Slope limitations of 15% do not apply to low pressure systems.

6.9. Shallow Field.

6.9.a. The construction of shallow systems shall in general be in accordance with the procedures and requirements for standard absorption fields. However, the depth of the trenches in natural ground may vary from 12 to 18 inches. The space between trenches may vary from six to 12 feet, and the depth of cover material may vary from six to 12 inches, depending on the trench depth.

6.9.b. There shall be cover material placed prior to the construction of the trench system.

6.9.c. Topography of the site may be level, less than 3% slope, or up to 15% slope if using a serial-type distribution system.

6.9.d. The percolation rate for design considerations shall be the rate recorded for the natural soil at installation depth.

6.9.e. Elevated Systems are systems installed at a depth of six inches into the original ground and have a portion of the gravel or distribution piping in select fill above the original ground. All applicable provisions of subsection 6.2 of this rule apply to elevated systems.

6.10. Individual Sewage Systems with Surface Water Discharge.

6.10.a. Individual systems with surface water discharge may receive consideration for approval under the following conditions:

6.10.a.1. To correct existing failures when other means of treatment and disposal have proven ineffective; and

6.10.a.2. On lots greater than two acres in size that cannot qualify for standard or shallow soil absorption systems. All mechanical systems with surface water discharge shall have a perpetual maintenance agreement as approved by the Commissioner.

6.11. Individual Home Aeration Units.

6.11.a. Individual home aeration units shall be used only when there is a provision for additional treatment, such as soil absorption or other means of effluent disposal approved by the Commissioner. The Commissioner may require ownership, operation, and maintenance of a home aeration unit to be under the control of a public or private utility regulated by the Public Service Commission.

6.11.b. Individual home aeration units shall bear the NSF seal demonstrating conformance with NSF Standard 40 or another recognized testing agency approved by the Commissioner.

6.11.c. Individual home aeration units may receive approval providing an applicant meets the following criteria:

6.11.c.1. Shall have a perpetual maintenance agreement approved by the Commissioner;

6.11.c.2. May use Class I NSF plants or equivalent where there is surface water discharge; and

6.11.c.3. May use Class II NSF plants or equivalent where there is a provision for additional treatment.

6.12. Intermittent Surface Sand Filters.

6.12.a. Effluent from a home aeration unit may discharge to intermittent surface sand filters.

6.12.b. Effluent from a surface sand filter may discharge to a stream after disinfection in accordance with the regulations and requirements pertaining to surface discharge of wastewater.

6.12.c. The design of intermittent surface sand filters preceded by a home aeration unit shall be on a filtration rate of 10 gallons per day per square foot. There shall be two filters of design size to provide for alternation of operation.

6.12.d. Intermittent surface sand filters serving individual sewage systems shall have an insulated cover.

6.12.e. The intermittent surface sand filter shall receive dosing by either a pump or sewage siphon.

6.13. Composting Toilets.

6.13.a. Utilization of composting toilets may be only in conjunction with an approved grey water treatment and disposal system.

6.13.b. The design and construction of a composting toilet shall meet the requirements of NSF Standard 41.

6.14. Incinerating and Chemical Toilets.

6.14.a. Use of incinerating and chemical toilets may be only in conjunction with an approved grey water disposal system.

6.14.b. The design, construction, and application of incinerating or chemical toilets shall receive approval by the Commissioner. The use of chemical or incinerating toilets may receive approval by the Commissioner in emergency situations, temporary usage situations, or for recreational residences, or isolated residences.

6.15. Grey Water Disposal Systems.

6.15.a. Those houses served by a grey water disposal system shall have a house sewer of not more than two inches in diameter.

6.15.b. Houses served by grey water disposal systems shall not have garbage disposal units connected to the grey water disposal system.

6.15.c. Manufactured grey water disposal systems shall receive approval by the Commissioner.

6.15.d. Non-commercial grey water disposal systems shall consist of the following:

6.15.d.1. A soil absorption field designed on the basis of a 30 percent reduction in water usage, and constructed in accordance with the design requirements for the standard soil absorption fields; and

6.15.d.2. A septic tank sized according to the following:

6.15.d.2.A. For four or fewer bedrooms, the minimum tank capacity shall be 1,000 gallons; and

6.15.d.2.B. For each additional bedroom, the minimum tank capacity shall be 250 gallons per bedroom.

6.16. Privies.

6.16.a. Every privy shall equip:

6.16.a.1. An earthen bottom pit or a watertight vault or other watertight receptacle with walls extending at least six inches above ground level.

6.16.a.2. A crowned curb constructed of compacted earth or other suitable material, at least six inches thick, extending from the top of the walls of the pit, vault, or receptacle, in all directions over the surface of the ground for a distance of 18 inches.

6.16.a.3. A riser that is fly tight when not in use.

6.16.a.4. There shall be an enclosed superstructure constructed with a vent pipe extending from the pit, vault, or receptacle to a point at least 24 inches above the roof of the of the superstructure or through the wall of the superstructure. The vent shall have a screen to prevent the entrance of flies and other insects.

6.16.a.5. Privy pits may have an earthen bottom if:

6.16.a.5.A. The location of the privy is below and 100 feet or more from a groundwater supply or individual well, and its location is so that the disposal of any leaching from there is in a manner that does not create a nuisance or insanitary condition.

6.16.a.5.B. The pit is four feet or less in depth and determined by the excavation of a seven-foot hole that rock or water table does not exist within three feet of the bottom of the pit.

6.16.a.6. There shall be no privy located within 20 feet of any dwelling, roadside cut, stream, establishment, or within 10 feet of any property line.

6.16.a.7. The construction and design of the privy superstructure, vault, pit, or other type receptacle shall be such as to prevent access to the vault or receptacle and the contents thereof, by flies, rats, and wild or domestic animals.

6.16.a.8. Privy vaults, pits or receptacles shall have the contents removed as often as necessary to prevent creating a nuisance or unsanitary condition.

6.16.a.9. There shall be an approved grey water disposal system installed to serve those residences with indoor plumbing or running water for sinks and showers. For those residences without indoor plumbing, there shall be a shallow leach trench installed for disposal of grey water as approved by the Commissioner.

6.17. Recirculating Toilets.

6.17.a. Recirculating toilets and the piping for the toilets shall be separate from and not connected to the potable water system of any residence or other structure under any circumstances. There shall be color coded pipe used to facilitate inspection and maintenance of the installations.

6.17.b. Recirculating toilets shall:

6.17.b.1. Be installed and operated in accordance with the manufacturer's instructions; and

6.17.b.2. Be approved by the Commissioner before installation.

6.18. Self-Contained Excreta Disposal Systems.

6.18.a. The design of self-contained excreta disposal systems shall be so as to prevent flies, rats, and wild or domestic animals from having access to the contents thereof.

6.18.b. The construction of all fixtures, tanks, or receptacles shall be of impervious, easily cleanable material.

6.18.c. Tanks and receptacles shall:

6.18.c.1. Be watertight and vented to the outside air;

6.18.c.2. Be constantly supplied with sufficient amounts of an approved chemical agent to process and deodorize the contents thereof; and

6.18.c.3. Have the contents removed and the tank or receptacle thoroughly cleaned as often as necessary to prevent creating a nuisance, or an unsanitary condition.

6.19. Sewage Holding Tanks.

6.19.a. The approval of sewage holding tanks shall only be for new construction after a contract awarded for the development of a public or private sewage collection system or treatment facility, or both, to serve the proposed new construction.

6.19.b. A holding tank shall be watertight and constructed of the same materials and by the same procedures as a watertight septic tank.

6.19.c. The liquid capacity of the holding tank shall be sufficient to contain a one-week design flow from the facility it is to service.

6.19.d. The location of holding tanks shall be in an area readily accessible for pumping under all weather conditions and where accidental spillage during pumping presents the least hazard to public health.

6.19.e. The location of holding tanks shall be in accordance with the distance requirements established for septic tanks in subsection 6.2 of this rule.

6.19.f. Construction and installation of the holding tank shall provide adequate access to the tank for pumping, cleaning and maintenance through manhole and cleanouts.

6.19.g. A holding tank installation shall equip an audiovisual high-level alarm when the tank is approximately two-thirds full and shall require pumping shortly. The location of the alarm shall be inside the facility served.

6.19.h. A contract with a licensed sewage tank cleaner with a valid permit for pumping and maintenance of the tank on a regular schedule shall be required.

6.19.i. A letter from a wastewater treatment plant owner accepting the pumpings shall be a requirement. This facility shall be approved by the Commissioner. There shall be an examination of the receiving wastewater treatment plant to ensure there shall be adequate treatment, and there shall be no effect on the normal operation of the wastewater treatment plant.

6.19.j. When it is necessary to protect the public health, the Commissioner reserves the right to require additional assurances before approving holding tanks.

6.20. Alternative and Experimental Sewer Systems.

6.20.a. The construction of alternative and experimental sewer systems may be where there is a suitable layer of soil, sufficient area and the natural slope is not excessive.

6.20.b. Alternative soil absorption systems presently approved for use are shallow fields, soil absorption mounds, shallow beds, low pressure pipe systems, elevated fields, evapotranspiration systems and unique systems designed for specific situations.

6.20.c. Alternative soil absorption systems may receive consideration for new construction on lots two acres and over providing soil and site limitations can be met.

6.21. Effluent Pumping for Individual Sewer Systems.

6.21.a. Pump type shall be non-clog submersible centrifugal effluent pumps or progressing cavity positive displacement pumps.

6.21.b. Pumps shall be readily removable and replaceable without dewatering the wet well.

6.21.c. The pump size should be to dose a soil absorption system two to four times a day. The recommended dosing cycle is twice a day; however, the dose shall be no more than 75% of the distribution pipe volume for all soil absorption systems using four-inch pipe.

6.21.d. The location of the pump shall be six to eight inches off the tank bottom to provide additional volume for sludge settlement.

6.21.e. The location of relays and electrical plug-ins or sockets shall not be inside the wet well or access manhole. The location of the devices must be above-ground in a weatherproof box or in the residence.

6.21.f. There shall be a high-water alarm placed within the residence.

6.21.g. Pipe used for the distribution system, the force main, shall be PVC SDR 21, PVC SDR 26, or Schedule 40,1.25 to two-inch diameter.

6.21.h. All parts of the distribution system, the manifold, and laterals, shall slope slightly toward the inlet to avoid freezing and ponding of water in the system between dosing.

6.21.i. The installation of piping shall be below the frost line.

6.21.j. The wet well shall be watertight and constructed of materials that will not corrode.

6.21.k. The wet well shall have an access manhole of 24 inches or greater in diameter. The installation of the manhole shall be level with or above the ground surface and the cover secured.

6.21.l. The size of a wet well shall be to provide adequate volume not only for one day reserve capacity, but also for single dose capacity plus additional capacity to maintain minimum depth for operation.

6.21.m. The wet well tank shall be set lower than the septic tank to provide usage of maximum capacity of the wet well.

W. Va. Code R. § 64-47-6