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A leach trench disposal system that disposes of effluent from a septic tank installed after the effective date of this chapter shall meet the following requirements:
(a) The minimum length of leach trench for a leach trench disposal system shall be 200 linear feet.
(b) Perforated pipe used in leach trench construction shall be IAPMO approved.
(c) Each leach trench shall consist of a trench 18 inches wide, 36 inches deep and be located no closer than 10 feet on center from any adjacent line. Clean washed rock or gravel, grading 1 to 1-1/2 inches, shall be placed around the perforated pipe. At least 12 inches of rock shall be placed under the perforated pipe and 4 inches above the perforated pipe.
(d) Leach trenches and perforated pipes shall be level with not more than 2 inches per 100 linear feet of variation in grade.
(e) Leach trench depth may exceed 36 inches below the surface when percolation testing substantiates that adequate soil conditions exist at the depth approved to receive and treat effluent. Additional rock shall be added to the trench to prevent the perforated pipe depth from falling below the approved depth. The maximum trench depth shall not exceed 60 inches unless steep slopes on the property make it impracticable to install the system without placing the leach trenches below 60 inches. If it is necessary to install leach trenches more than 60 inches below the surface, the property owner shall only be allowed to exceed 60 inches if the installation complies with resource protection provisions in sections 86.601 et seq., grading provisions in sections 87.101 et seq. and the California Occupational Health and Safety Act.
(f) In lieu of perforated pipe and clean washed rock or gravel required by this section to be placed in leach trenches, the Director may allow an applicant to use an alternative device that the Director determines achieves the same practical effect as the perforated pipe and washed rock or gravel, in disbursing and treating effluent.
(Amended by Ord. No. 3061 (N.S.), effective 5-11-67; amended by Ord. No. 6049 (N.S.), effective 6-11-81; amended by Ord. No. 7428 (N.S.), effective 2-4-88; amended by Ord. No. 9273 (N.S.), effective 12-15-00; amended by Ord. No. 10136 (N.S.), effective 4-15-11)