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SECTION 4 - PERCOLATION TESTING <br />Percolation testing shall be done on -all proposed drainfield sites to <br />help determine the natural absorption capability of the soil. For new <br />systems, at least 4 percolation tests shall be -made within the primary <br />drainfield area and at least 2 percolation tests within the alternate <br />drainfield area. For drainfield additions to existing systems, at <br />least two percolation tests should be made in the expansion area. <br />Percolation Test Procedure: <br />1. <br />Type of Test Hole <br />1 <br />' <br />SECTION 4 - PERCOLATION TESTING <br />Percolation testing shall be done on -all proposed drainfield sites to <br />help determine the natural absorption capability of the soil. For new <br />systems, at least 4 percolation tests shall be -made within the primary <br />drainfield area and at least 2 percolation tests within the alternate <br />drainfield area. For drainfield additions to existing systems, at <br />least two percolation tests should be made in the expansion area. <br />Percolation Test Procedure: <br />1. <br />Type of Test Hole <br />A hole with horizontal dimensions of six inches and vertical <br />si.des�shall be dug or bored to the depth of the proposed <br />absorption trench. <br />2. <br />Preparation of Test Hole <br />The bottom and sides of the hole shall be carefully scratched <br />with a knife blade or sharp pointed instrument to remove any <br />smeared soil surfaces and to provide a natural soil interface <br />• <br />into which water may percolate..' All loose material shall be <br />removed from the hole and two (2)* inches of coarse sand or <br />Ane gravel shall be added to protect the bottom from scouring. <br />and sediment. <br />3. <br />Saturation and Swelling of the Soil <br />The hole shall'be carefully filled with clear water ta_a minimum <br />depth -of twelve (12) inches over the gravel. Water shall be <br />kept in the hole for at least four (4) hours, and preferably <br />overnight, by refilling if necessary, or by supplying a surplus <br />reservoir of water, such as in -an automatic siphon. In sandy <br />soils containing little or no clay, the swelling procedure shall <br />not be required and the test may be made as described under <br />Item.2diiD3 after the water from one filling of the hole has <br />completely seeped away. <br />4. <br />Percolation Rate Measurement - <br />With the -exception of sandy soils, percolation rate measurements <br />shall be made on the day following the procedure described <br />under Item (C) above and as follows: A percolation rate data <br />sheet shall.be kept and submitted for each test. <br />-17 <br />