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CONCLUSIONS AND RECOMMENDATIONS In summary, the soil conditions examined on the homesite parcel of the Site were found to be suitable for septic systems utilizing leach lines or filter beds. A satisfactory soil percolation rate of 3.33 min/in was observed in the percolation test location. The soil in the test location was found to be silty sand. Based on maps reviewed, the depth of ground water based on recent aquifer levels is approximately 32 to 33 feet below ground surface. The ground -water flow is to the south or southeast at a rate of approximately 4 to 7 feet per mile in the vicinity of the Site. Because of the percolation rate between 1.0 and 5.0 min/in encountered in the test hole, the San Joaquin County Environmental Health Department will require a 20 -foot separation from the bottom of the dispersal systems to ground water. Based on the predicted depth to water, no modification to standard shallow systems should be necessary. A water sample was collected from the domestic well on the Site as part of this investigation. Nitrate was detected in the sample at a concentration of 18.6 mg/L-N, substantially above the MCL of 10 mg/L-N. DBCP was detected in the sample at a concentration of 0.29 �Ag/L, above the MCL of 0.2 µg/L. In the test results from the irrigation well provided by Prof. Shaw, nitrate was detected at a concentration of 14.2 mg/L-N, also well above the MCL. Based on the methods and assumptions described, the nitrate loading calculation indicates that the use of on-site septic tanks and drain field systems on the Site have the potential to cause a buildup of nitrate in the aquifer up to 6.5 mg/L-N, well below the maximum drinking water standard of 10 mg/L-N. Based on the result of the nitrate loading calculation, no nitrate mitigation is recommended at this time. LOGE 2124 Page 14