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• CONCLUSIONS AND RECOMMENDATIONS In summary, the soil conditions examined near the proposed septic system drain fields appear to be suitable for standard septic systems utilizing leach lines, leach lines and sumps, or filter beds. Satisfactory soil percolation rates of 4.46 and 25 minutes per inch were observed at the test locations. Based on the rapid percolation rate identified at location P1, a septic system installed in that area will require a 20-foot separation from the bottom of the dispersal system to ground water; this requirement may limit the use of sumps in that area. Septic system construction should follow the San Joaquin County On-Site Wastewater Disposal Standards (2016). The depth of ground water based on recent aquifer levels is approximately 24 to 43 feet below the ground surface, depending on the location on the Site. The ground-water flow direction is toward the north or northeast at a rate of approximately 4 to 7 feet per mile in the vicinity of the Site. Delicato Family Vineyards is considered a Small Public Water System. This classification includes specific testing requirements beyond those required for the Soil Suitability Study; as a result, no water sample was collected as part of this investigation. 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 3.70 mg/L-N. • This level falls below the US EPA drinking water recommendation of 10 mg/L-N. It should be noted that ground water nitrate levels in some areas beneath the Site already exceed the US EPA's recommendation, as identified during monitoring well testing required by the Central Valley Regional Water Quality Control Board. We believe the Site suitable for development with the use of standard septic systems. Based on the satisfactory result of the nitrate loading calculation, no nitrate mitigation is recommended. • LOGE 1714 Page 20