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• Expected On-Site Maximum Septic Tank Usage Maximum expected septic usage on the Site would be from the existing home and a potential future second unit dwelling on the homesite parcel. No construction is planned. Ground Water Information Depth and Gradient Live Oak reviewed ground-water elevation information available from the San Joaquin County Flood Control and Water Conservation District to determine the ground-water levels near the Site. Data from the spring and fall of 2016 were the most recent available from this source (Plates 5 and 6). According to an analysis of these maps, the ground-water elevation is approximately 15 to 20 feet below mean sea level; the ground-water flow is to the north or northeast at a rate of approximately 12 to 33 feet per mile. Given that the ground elevation of the Site is approximately 65 feet above sea level, based on the County ground water maps the depth to ground water below the Site is estimated to range between 80 to 85 feet. Potential Ground Water Contamination Issues • The Soil Suitability Study is not intended to be an investigation into ground-water contamination sources, and no such investigation was conducted. Many sources can contribute to ground water contamination, including leaking underground storage tanks, agricultural activities, dairies and cattle ranches, septic systems, and storm water infiltration. Agricultural activities and the use of septic systems in the area are known ground-water contamination sources with the potential to impact the Site. Live Oak reviewed the San Joaquin County Environmental Health Department's Water Well Data Table dated March 10, 2009 for nearby addresses that have been tested for nitrate and dibromochloropropane (DBCP). Eight wells were identified at addresses within approximately one-half mile of the subject Site. Six of the wells had been tested for DBCP; it was detected in five wells, at concentrations of 0.090 to 4.27 µg/L. Five of the wells had been tested for nitrate; it was detected in all five at concentrations of 1.0 to 50 mg/L- NO3. The Maximum Contaminant Level (MCL) set by the US EPA for nitrate as NO3 is 45 mg/L (equivalent to 10 mg/L-N). The MCL for DBCP is 0.2 µg/L. On-Site Wells A domestic well and an irrigation well are located on the Site. No well permits were identified for the Site at the San Joaquin County Environmental Health Department. • LOGE 1721 Page 3