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Soil Suitability and Nitrate Loading Evaluation CTE Job # 25-0726G Custom Home 5388 Fig Road Manteca, California May 18, 2020 Page S of 9 Appendix -A. All test holes were backfilled and surface restored to original condition upon completion of testing. 8.0 PERCOLATION TESTING Our subsurface investigation included conducting leach field soil suitability evaluations via percolation testing. The evaluation included the drilling and testing of one percolation test hole performed at a depth of 36 -inches at the proposed (P-1) leach field location. The field testing was performed under San Joaquin County EHD "Onsite Wastewater Treatment System Permit" Number SR0081606. With exception of conditions described below, the percolation test was performed in general conformance with San Joaquin County Environmental Health Department procedures shown on EHD 42-01-002, Revised 4/14/2018. The final readings of the test were observed/inspected by a San Joaquin County EHD inspector. Percolation test data is presented in Appendix A and a copy of the certified field data is included in Appendix B. 8.1 Percolation Testing Procedure Upon completion of the percolation test hole drilling, loose material was removed and a 3 -inch diameter open-ended slotted drain pipe was installed to control potential sidewall caving of the hole. Pre -saturation of the soils to be tested was accomplished by adding water to 12 -inches above the base each test hole the day preceding the test. After 30 minutes in test hole "P-1'' a 9 -inch column of water "dissipated" in test hole "P -I". Percolation testing was performed the following day. Immediately after the 24-hour pre -saturation period, a 6-inche column of water was added to (P-1) above the top of the 2 inches of gravel placed at the base of the test hole. Recordings were made of the change (drop) in water level at regular time intervals and water level was refilled to 6 - inches above the gravel after each interval. Specific details are included on the attached percolation test data sheet located in Appendix -A. 8.2 Percolation and Infiltration Rates The soil percolation rate is defined by the average time in minutes for a I -inch column of water to "seep" into the soil. Percolation rate was calculated in minutes per inch (MPI) by dividing the