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Expected On-Site Maximum Septic Tank Usage Maximum expected septic usage on the Site would be from the two existing systems on the proposed homesite parcel. 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 fall of 2013 and spring of 2014 were the most recent available from this source. According to an analysis of these maps (Plates 5 and 6), the ground water elevation is 30 to 40 feet above mean sea level; the ground-water flow is to the north or north-northeast at a rate of 10 to 15 feet per mile. Given that the ground elevation of the Site is 45 to 50 feet above sea level, based on the County ground water maps the depth to ground water below the Site is estimated to range between 5 to 20 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). Four wells were identified at addresses within approximately 1.5 miles of the subject Site. Nitrate was detected in the wells at concentrations ranging from 26.0 to 46.9 mg/L. Only one of the wells had been tested for DBCP; it was not detected. The Maximum Contaminant Level (MCL) set by the US EPA for nitrate as NO3 is 45 ppm. The MCL for DBCP is 0.2 ug/L. On-Site Wells One domestic well and one irrigation well exist on the Site. Three well permits were identified for the Site at the San Joaquin County Environmental Health Department: • May 1980 permit for repair to domestic well (25144). • April 1981 permit for reconditioning of irrigation well (25144). • August 1992 permit for system repair to irrigation well (25000; well location unclear). LOGE 1502 Page 3