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CONCLUSIONS AND RECOMMENDATIONS In summary, the soil conditions near the existing septic system drain field were found to be suitable. A satisfactory soil percolation rate of 27.2 min/in was observed by TEST in 2010. The depth of ground water based on recent aquifer levels is approximately 56 to 59 feet below ground surface. Ground water flows down down to the south or south-southeast at a rate of approximately six feet per mile. In 2010, TEST advanced a soil boring to 50.5 feet below ground surface; no ground water was encountered. The highest recent ground-water levels for the area were experienced in spring of 1983 and 1999; at these times, ground water would have been present at approximately 44 to 45 feet below ground surface. Because the percolation rate encountered falls between 5.0 and 30 min/in, the San Joaquin County Environmental Health Department will require an eight-foot separation from the bottom of the dispersal system to ground water. Based on depth to water in the area, no modifications to standard systems should be required. Live Oak collected a water sample from the domestic well that serves the California Islamic Center as part of this investigation. Nitrate was detected in the sample at a concentration of 2.9 mg/L-N, well below the MCL of 10 mg/L-N. DBCP was not detected in the sample. In 2010, TEST collected two samples from the domestic well that serves the houses on the Site; nitrate was detected at 59 and 60 mg/L; the TEST report indicates that the results represent mg/L-NO3 (equivalent to 13 mg/L-N). DBCP was detected at 0.097 and 0.096 ug/l_ (below the MCL of 0.2 µg/L). It is inferred from these results that the houses may receive water from an older, relatively shallow well, while the California Islamic Center building receives water from the newer, deeper well. If the houses are to continue receiving their water supply from the older well, it is recommended for health reasons that bottled water be consumed until the concentration of nitrate can be reduced to below the MCL. Based on a review of the San Joaquin County Environmental Health Department map of nitrate detections in nearby wells, four wells within a half-mile radius of the subject Site have been tested for nitrate. Nitrate was detected in two of these wells at concentrations between 0.1 and 5.0 mg/L-N, and in two at concentrations above 10 mg/L-N. According to the DBCP map, three wells within a half-mile radius of the Site have been tested for DBCP; it was detected in one of the wells at a concentration over 0.2 [g/L; no DBCP was detected in the other two wells. LOGE 1939 Page 16