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CONCLUSIONS AND RECOMMENDATIONS <br /> In summary, the soil conditions examined near the location of the septic system drain <br /> field appear to be suitable. A satisfactory soil percolation rate of 2.4 minutes per inch <br /> was observed. <br /> The depth of ground water based on recent aquifer levels is approximately 49 to 57 feet <br /> below the ground surface, depending on the season. The ground-water flow direction is <br /> to the south or south-southeast at a rate of approximately three to six feet per mile in <br /> the vicinity of the Site. <br /> The on-site domestic water well was tested for nitrate and DBCP. Nitrate was detected <br /> at a concentration of 126 mg/L-NO3 (28 mg/L-N) in the water sample. DBCP was <br /> detected in the sample at a concentration of 0.28 txg/L. The US EPA has set the <br /> Maximum Contaminant Level (MCL) for nitrate as NO3 at 45 mg/L (10 mg/L-N) and the <br /> MCL for DBCP at 0.2 ppb (equivalent to [g/L). Because of the levels of nitrate and <br /> DBCP detected, we would recommend that the occupants of the Site consume bottled <br /> water until such time as the concentrations can be reduced below the MCL. Use of <br /> certain water filters or deepening of the domestic well could potentially improve the <br /> water quality. The San Joaquin County Environmental Health Department may be able <br /> to provide additional suggestions. <br /> Based on the current project, the use of on-site septic tanks and drain field systems on <br /> the Site is not expected to cause a buildup of nitrate in the aquifer above 5.05 to 7.07 <br /> mg/L-N. These levels fall below the US EPA drinking water recommendation of 10 <br /> mg/L-N. It should be noted that the surrounding aquifer may already contain nitrate <br /> above this level, as indicated by the results of the test on the domestic well. <br /> We believe the Site suitable for development with the use of standard septic systems. <br /> LOGE 1124 Page 15 <br />