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CITY OF OR ON 0 <br />GENERAL CONSTRUCTION REQUIRFYIENTS <br />FILL TRENCH DRAINFIELD SYSTEM <br />TO BE USED WHERE: Seasonal perched water table is deeper than 5 feet. <br />Percolation rate is between 60 and 90 min. per inch. <br />Slope is 18% or less. <br />CONNECTION TO <br />HOUSE House to tanks may be PVC (ASTM D-3034 or better), <br />cast iron or clay tile. PVC should be sand -bedded <br />in flat runs over long distances. No outside air test <br />required but joints must be tight. <br />TANKS Two (2) precast concrete tanks are required. Min. size <br />1000 gal. and 750 gal.; we recommend 2 1000's. Tanks <br />must have 20" manhole riser to within 12" of final <br />grade, and at leas:. one 4"-6" inspection stack to <br />surface. Baffles must be ac d resistant and may be <br />plastic, fiberglass, or precast with tank. <br />DRA INFIELD Trenches in top 3' of natural undisturbed soil. Not <br />in cut or fill areas. Place at least 6" and not more <br />than 12" or <br />sand oma -.Zoe} -between <br />bottom of scarified trench and =ter rock. Maximum <br />width 36". Maximum length per line 1001. Rock 6-12" <br />below pipe and 2" over top. Tile may be PVC or plastic <br />with It," holes every 36" or closer. Use hay or un- <br />treated building paper over rock. Backfill - maximum <br />depth 36", minimum depth 8", 12-24" preferred. Trench <br />bottom must be level or have slope of not more than <br />4" per 1001. <br />DISTRIBUTION Drop boxes or distribution box depending on layout <br />and topography. A pre.G,ire distribution system using <br />13-15" pipe and pump from t, .ks is high1Q recommended for <br />the fill trench system. <br />-• r <br />Ok <br />PUMPING : If pumping is needed between tank and drainfield, <br />pump should go in a 3rd tank or in baffled chamber <br />in 2nd tank. The idea is to retain the 2nd tanks <br />capacity for solids retention. An alarm device and <br />reserve capacity of one days sewage flow are required. <br />QUESTIONS ? CALL THL SEPTIC SYSTEM INSPECTOR AT 473-7357• <br />