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CONCLUSIONS AND RECOMMENDATIONS In summary, the soil conditions near the proposed septic system drain field were found to be suitable. A satisfactory soil percolation rate of 31.25 min/was observed at the percolation test location. The depth of ground water based on recent aquifer levels is approximately 85 to 98 feet below ground surface. Ground water flows down to the east-northeast at a rate of approximately eight to 17 feet per mile. 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 60 to 90 feet below ground surface. A water sample was collected from the domestic well on the Site as part of this investigation. Results of the testing will be provided as an addendum to this report as soon as they become available from the laboratory. Based on a review of the San Joaquin County Environmental Health Department map of nitrate detections in nearby wells, five wells within a half-mile radius of the subject Site have been tested for nitrate. Nitrate was detected in four of these wells at concentrations between 0.1 and 5.0 mg/L-N, and in one at a concentration between 5.1 and 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 not detected in any of the wells. Based on the current project, the use of on-site septic tanks and drain field systems on the Site is not expected to cause a buildup of nitrate in the aquifer above 7.2 mg/L-N. This level falls below the US EPA drinking water recommendation of 10 mg/L-N. We believe the Site suitable for standard septic systems utilizing leach lines and seepage pits. Based on the satisfactory result of the nitrate loading calculation, no nitrate mitigation is recommended for the current project. LOGE 1933 Page 13