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Percolation Test Procedure The San Joaquin County Environmental Health Department (EHD) has adopted the following procedure in order to evaluate and process percolation results uniformly, effectively and quickly. Obtain Application for Percolation Test Permit: • Fee is$125 per test hole or$625 for 5 or more test holes. • Indicate the test hole location(s)on the permit application plot plan. • 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. • Call (209)953-7697 to schedule an inspection 48 hours in advance. Preparation of Test Hole(s) Preparation of Test Hole(s)for Deep Perc Test: Test Hole(s)dimensions: Test Hole Dimensions: Diameter=4 inches to 12 inches Diameter=4 inches to 12 inches Depth(Consistent with leach field)=18"-42' Depth=42 inches to 25 feet,Minimum 10 feet above water table. • Scratch or score sides to remove any smeared soil surfaces. • Pre-soak Test Hole(s)by adding water 6"above selected stratum. • Remove loose material from hole. Maximum water level allowed=3 feet above selected stratum • Add 2 inches of course sand or fine gravel. 0 Red Zone area requires 25'deep test hole(s)or soil stratum that meets • Saturation: Pre-soak Test Hole(s)24 hours before test by adding water a minimum percolation rate for pit testing. minimum of 12 inches over gravel. The EHD is to be notified of start of Percolation Test. PROCEDURE M PROCEDURE#2 PROCEDURE#3 If water remains in the test hole overnight If NO water remains in test h ole overnight Sandy soils(or other soils)in which the first 6 inches of water seeps away in less than thirty(30) • Add clear water to approximately 6 inches 6 Add clear water to bring depth of water in the hole minutes after the overnight saturation period over the gravel. to approximately 6 inches over the gravel. • From a fixed reference point,measure the 0 From a fixed reference point, measure the drop in • Refill the hole to approximately 6 inches above drop in water level over a thirty(30)minute water level at thirty(30)minute intervals for four the gravel. period. 4 hours, refilling 6 inches over the gravel as a From a fixed reference point,take the readings • Calculate the percolation rate in minutes per necessary. 10 minutes apart over a one(1)hour period. inch. • Use the latest reading of the four(4)hour period & Use the latest reading change; calculate to calculate percolation rate in minutes per inch. percolation rate in minutes per inch. At the time of the percolation test inspection, Environmental Health Staff will: • Review application and parcel map for location accuracy and verify appropriate procedure used. • Inspect test hole construction and review raw field data recorded prior to arrival. • Observe and document the readings during the final 30 minutes of the test on the EHD"Percolation Test Application." • Correct any data on the application and sign the percolation record sheets. Source: Manual of Septic Tank Practices,U.S.Dept.of H.E.W.(1967),as founded and modified for San Joaquin County. San Joaquin County EHD Policy#98-02. EHD 42-01-002 Revised 5/24/2021 SAN JOAQUIN COUNTY EHD