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SAN:JOAQUIN <br />COUNTY <br />Environmental Health Department <br />Percolation Test Procedure <br />The San Joaquin County Environmental Health Department (EHD) has adopted the following procedure in order to evaluate and process percolation <br />results uniformly, effectively and quickly. <br />Obtain Application for Percolation Test Permit: <br />Fee is $152 per test hole or $760 for 5 or more test holes. <br />Indicate the test hole location(s) on the permit application plot plan. <br />Percolation Test Hole(s) shall not be located within 100 feet of any well or violation any other set-back requirements for a septic system. <br />Call (209) 953-7697 to schedule an inspection 48 hours in advance. <br /> <br />1 <br /> <br />Preparation of Test Hole(s) <br />Test Hole(s) dimensions: <br />Diameter = 4 inches to 12 inches <br />Depth (Consistent with leach field) = 36 - 42' <br />Scratch or score sides to remove any smeared soil surfaces. <br />Remove loose material from hole. <br />Add 2 inches of course sand or fine gravel. <br />Saturation: Pre-soak Test Hole(s) 24 hours before test by adding water a <br />minimum of 12 inches over gravel. The EHD is to be notified of start of <br />Percolation Test. <br />Preparation of Test Hole(s) for Deep Perc Test: <br />Test Hole Dimensions: <br />Diameter = 4 inches to 12 inches <br />Depth =42 inches to 25 feet, Minimum 10 feet above water table. <br />Pre-soak Test Hole(s) by adding water 6" above selected stratum. <br />Maximum water level allowed = 3 feet above selected stratum <br />Red Zone area requires 25' deep test hole(s) or soil stratum that meets <br />minimum percolation rate for pit testing. <br /> <br />PROCEDURE #1 <br />If water remains in the test hole overnight <br />Add clear water to approximately 6 inches <br />over the gravel. <br />From a fixed reference point, measure the <br />drop in water level over a thirty (30) minute <br />PROCEDURE #2 <br />If NO water remains in test h ole overnight <br />Add clear water to bring depth of water in the hole to <br />approximately 6 inches over the gravel. <br />From a fixed reference point, measure the drop in <br />water level at thirty (30) minute intervals for four <br />PROCEDURE #3 <br />Sandy soils (or other soils) in which the first 6 <br />inches of water seeps away in less than thirty (30) <br />minutes after the overnight saturation period <br />Refill the hole to approximately 6 inches above <br />the gravel. <br />From a fixed reference point, take the readings <br />10 minutes apart over a one (1) hour period. <br />period, <br />Calculate the percolation rate in minutes per <br />inch. <br />(4) hours, refilling 6 inches over the gravel as <br />necessary. <br />Use the smallest reading of the four (4) hour <br />period to calculate percolation rate in minutes per <br />inch. <br />Use the smallest reading change; calculate <br />percolation rate in minutes per inch. <br />At the time of the percolation test inspection, Environmental Health Staff will: <br />Review application and parcel map for location accuracy and verify appropriate procedure used. <br />Inspect test hole construction and review raw field data recorded prior to arrival. <br />Observe and document the readings during the final 30 minutes of the test on the EHD "Percolation Test Application." <br />Correct any data on the application and sign the percolation record sheets. <br />Source: Manual of Septic Tank Practices, U.S. Dept. of H.E.W. (1967), as founded and modified for San Joaquin County. <br />San Joaquin County EHD Policy #98-02. <br />EHD 42-01-002 Revised 4/14/2018 <br />1868 E. HazeIton Avenue I Stockton, California 95205 I T 209 468-3420 I F 209 464-0138. I www.sjcehd.com