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CONCLUSIONS AND RECOMMENDATIONS In summary, the soil conditions examined near the proposed septic system drain field were found to be suitable for a septic system utilizing leach lines with seepage pits. A satisfactory soil percolation rate of 17.9 min/in was observed in the shallow soil zone at the test location. The soil in the test location was found to be clay. The depth of ground water based on recent aquifer levels is approximately 73 to 78 feet below ground surface. The ground-water flow is to the northeast at a rate of approximately 11 to 24 feet per mile. 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 8.5 mg/L-N, below the MCL of 10 mg/L-N. DBCP was not detected in the sample; the MCL for DBCP is 0.2 ug/L. Based on maps reviewed, neither nitrate nor DBCP appear to be present over their MCLs in nearby wells. 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 has the potential to cause a buildup of nitrate in the aquifer up to 10.7 mg/L, just above the maximum drinking water standard of 10 mg/L-N. No evidence has been identified of nitrate impacts exceeding the MCL in the area, however, and the soil conditions are favorable for nitrate reduction. Based on the depth to ground water, clay soils present, and nitrate test results in the area, the actual nitrate impact to ground water beneath the Site may be considerably less than predicted, and it is the opinion of Live Oak that an engineered nitrate-mitigating septic system is not warranted in this location. Although Live Oak cannot make engineering recommendations, we are aware that in the past the San Joaquin County Environmental Health Department has allowed the use of an oversized septic tank to mitigate nitrate impacts; this option may be worth considering for the Site. LOGE 2118 Page 14