Laserfiche WebLink
Sewage disposal *ste=is <br />§SM <br />13. The drainfield rock shall completely encase the disposal <br />pipeB to a depth of at least I inches. The top of the drainfield <br />rock in trenches, beds, and mounds must be level in all <br />directions. <br />14. The filter material shall be covered with either a permeable <br />synthetic fabric or a 4 inch layer of compacted hay or straw <br />covered with untreated building paper. Where a drop bogy; <br />distribution system is used to fill a trench to within 2 inches <br />of the top of the drainfield rock, a permeable synthetic fabric <br />must be used to cover the drainfield crock. <br />15. The trenches or beds shall be backfilled with the excavated <br />material and slightly crowned above finished grade to allow <br />for settling. The backfill shall not be completed to a density <br />greater than that of the original soil. <br />16. The minimum depth of cover over the distribution pipes shall <br />be a least 8 inches. The maximum depth of cover over the <br />distribution pipes shall be no more than 36 inches and <br />preferably no more than 24 inches. <br />17. A grass cover shall be established by the owner or the <br />owner's agent over the soil treatment area. <br />d. Dual Field Systems&, <br />1. Dual field systems shall be used only where the percolation <br />rate is slower than 5 minutes per inch. <br />2. Dual field systems shall be sized, designed, and constructed <br />as set forth above for standard systems except as follows: <br />a) The soil treatment area shall be divided into two or more <br />parts. <br />b) Alternating soil treatment areas shall each be <br />connected to a valve box outlet. <br />3. A part of the soil treatment area shall be used no more than <br />one year unless inspection of the effluent level indicates that <br />a longer duration can be used. <br />e . Slowly Permeable Soils <br />1. Excavation for the purpose of constructing a soil treatment <br />system must not be made in any soil layer having a <br />percolation rate slower than 120 minutes per inch. <br />2. Excavation for the purpose of constructing a soil treatment <br />system. must not be made in a soil layer having a percolation <br />rate slower than 60 minutes per inch unless the moisture <br />content is lower than the plastic limit of the soil. <br />Printed 12/28!90 Page 253 <br />