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CONCLUSIONS AND RECOMMENDATIONS <br /> In summary, the soil conditions examined near the proposed septic system drain field <br /> were found to be suitable for a standard septic system utilizing leach lines and seepage <br /> pits. Satisfactory soil percolation rates of 35.7 min/in (shallow) and 5.3 min/in (deep) <br /> were observed at the test locations. The soils in the test locations were found to be <br /> mixtures of sand and silt. <br /> The depth of ground water based on recent aquifer levels is approximately 50 to 62 feet <br /> below ground surface. The ground-water flow is to the northeast at a rate of <br /> approximately 7 to 21 feet per mile. <br /> Because of the percolation rate between 5.0 and 30.0 min/in encountered in the deep <br /> test hole, the San Joaquin County Environmental Health Department will require an 8- <br /> foot separation from the bottom of the dispersal system to ground water. Based on the <br /> depth to ground water beneath the Site, no modification to standard systems should be <br /> necessary to meet this requirement. <br /> A sample was collected from the domestic well on the Site by FGL Environmental. <br /> Nitrate was detected in the sample at a concentration of 0.4 mg/L-N, and DBCP was not <br /> detected. <br /> Based on the methods and assumptions described, the nitrate loading calculation <br /> indicates that the use of on-site septic tanks and drain field systems on the Site has the <br /> potential to cause a buildup of nitrate in the aquifer up to 0.7 mg/L-N, well below the <br /> maximum drinking water standard of 10 mg/L-N. Because of the favorable result of the <br /> nitrate loading calculation, no nitrate mitigation is recommended at this time. <br /> LOGE 2107 Page 14 <br />