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CONCLUSIONS AND RECOMMENDATIONS In summary, the soil conditions examined near the existing septic system drain field were found to be suitable for a standard septic system. A satisfactory soil percolation rate of 41.67 min/in was observed in the shallow soil zone at the test location. The soil in the test boring was found to be silty clay. The depth of ground water based on recent aquifer levels is approximately 17 to 19 feet below ground surface. The ground-water flow is to the east at a rate of approximately eight to 11 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 5.4 mg/L-N, below the MCL of 10 mg/L-N. DBCP was not detected. Based on County maps reviewed, nitrate and DBCP do not appear to be of concern in nearby wells. Based on the method 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 9.8 mg/L-N with a one- bedroom second unit dwelling, just below the MCL of 10 mg/L-N. The nitrate loading calculation indicates the potential to cause a buildup of nitrate in the aquifer up to 10.6 mg/L-N with a two-bedroom second unit dwelling; this result is slightly above the US EPA drinking water recommendation of 10 mg/L-N. However, based on the conservative nature of the calculation, low levels of nitrate in nearby wells, and clay soil present in the area, it is the professional opinion of Live Oak that septic effluent from the proposed project is unlikely to contribute substantially to a build-up of nitrate in the ground water. Use of a standard, shallow septic system (leach lines or a filter bed) should be permitted. LOGE 20-48 Page 14