Laserfiche WebLink
PERCOLATION TEST PROCEDURE FOR SAN JOAQUIN COUNTY <br /> 1 . Measurments of the Percolation test Hole. <br /> A. Diameter = 4 inches to 12 inches. <br /> B. Depth = of leach field - 36 inches . <br /> II . Preparation of the Test Hole. <br /> A. Scratch or Score sides to remove any smeared soil surfaces. <br /> B. Remove loose material from hole <br /> C. Add 2 inches of course sand or fine gravel. <br /> III . Saturation. <br /> A. Presoak Test Hole for 24 hours. <br /> IV. Procedure #1 - If water remains in the hole overnight . <br /> A. 24 hours after water is first added to the hole, add clear <br /> water to approximately 6 inches over the gravel . <br /> B. From a fixed reference point, measure the percolation rate <br /> over a thirty (30) minute period. <br /> C. Calculate the percolation rate in minutes per inch: <br /> V. Procedure #2 - if no water remains in test hole overnight . <br /> A. Add clear water to bring depth of water in the hole to <br /> approximately 6 inches over gravel . <br /> B. From a fixed reference point , measure the drop in water level <br /> at approximately 30 minute intervals for four (4) hours, <br /> refilling 6 inches over the gravel as necessary. <br /> C. Use the reading during the last 30 minutes of the four hour <br /> period to calculate percolation rate in minutes per inch. <br /> IV. Procedure #3 - in sandy soils (or other soils) in which the first <br /> 6 inches of water seeps away in less that 30 minutes after the <br /> ' overnight swelling period. <br /> A. Refill the hole to approximately 6 inches above the gravel. <br /> ' B. Take the readings 10 minutes apart over a one hour period. <br /> C. Use the reading obtained during the last minutes to calculate <br /> percolation rate in minutes per inche. <br /> Source: Manual of Septic Tank Practices, U .S. Dept . of H.E_W. ( 1967) <br /> PC>, ty &.t.1 InSme - <br />