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C. DIS RIBUIION BOX: 1. PURPOSE: The distribution box distributes the liquid from the septic tank equally among two or more lines of the leaching field. The distribution box also provides an inspection point and may be used to control the flow of the effluent to the leaching field. 2. Inlets and outlets of any distribution box shall be water tight. A five foot (5') A.B.S. Schedule 40 tightline with continuous soil barrier shall be installed between the distribution box and the leach line. D. SUB-SURFACE DISPOSAL FIELD 1. LEACHING LINES: a. PURPOSE: Leaching lines provide additional treatment and disposal for sewage. b. MATERIALS: The line shall consist of approved perforated pipe. The pipe shall have an inside diameter of 4 inches. The rock used in the disposal field shall be 1 inch to 2 1/2 inches in diameter. c. LOCATION: Leach,lines shall be no closer than twelve feet (12') center to center. The total amount of rock in the trench must be a minimum of 18 inches, 12 inches below the pipe and 2 inches above the pipe. d. DESIGN: The trench shall be twenty four inches (24") side and shall be no deeper than forty two inches (42") deep. Leach lines shall have a grade of one inch (1") to three inches (3') per one hundred feet (1001). The bottom of the leach line shall be a minimum of five feet (5') above the water table. e. All leach lines, sumps, and pits shall be covered with 151b felt paper or equivalent. Straw hay may also be used. f. The total length of the leaching line shall be specified by the Director of Environmental Health. NO ONE LINE SHALL EXCEED A TOTAL OF 100 FEET IN LENGTH. 2. SEEPAGE PITS: Every seepage pit shall have a minimum of forty feet (4(Y) of leaching line between the septic tank and the pit, unless otherwise approved by the Director of Environmental Health. a. PURPOSE: The seepage pit provides an area for absorption of liquid wastes into the soil. b. MATERIALS: The seepage pit shall be filled with rocks two inches (2") to four inches (4") in diameter to the level of the outside top of the distribution box or Tee. A three foot (3') soil barrier and ABS Schedule 40 or equivalent tightline shall precede each seepage pit or sump. The rock and distribution box or Tee shall be covered with fifteen pound (15 Ib) building paper prior to back filling. The seepage pit shall contain a vertical four inch perforated leach pipe extending to the pit bottom and connected with a four inch capped Tee to the tight line or connected through an open bottom distribution..box. C. DESIGN: The seepage pit shall have a minimum diameter of thirty three inches (33") with a MAXIMUM DEPTH OF 25 FEET. Illustration "D" shows an approved circular, rock-filled pit. Other types of seepage pits may be substituted for circular pits. A ten (10) foot separation is required between the bottom of a seepage pit and the water table. A three foot (37 ABS Schedule 40 or equivalent tightline, with continuous soil barrier, shall be installed between the leach line and pit or sump. 3. EXPANSION AREA: For single family dwellings, open land area must be available for addition to the original sewage system. This land area is to be at least 50% of the amount required by the original sewage system, or by what has been determined by an engineered percolation test. 4. REPAIRS: a. A minimum sewage system repair shall equal the amount of leach line needed for an additional bedroom. A sewage system repair shall meet existing standards of construction and design. b. All existing brick lined or open pits shall be completely rock-filled if intended for continued use or destroyed if it is to be abandoned. C. The tops of any redwood tanks that are dry-rotted must be replaced with either a top grade redwood or concrete top. If either a redwood or metal septic tank shows signs of deterioration to the point it is no longer water tight, the entire tank must be replaced. C�