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Expected On-Site Maximum Septic Tank Usage Maximum expected septic usage on the Site would be from the existing system and the future residential system on Parcel 2. However, County regulations may allow the placement of a secondary residence on each parcel at some point in the future. Septic system design should be based on the On-Site Wastewater Disposal Standards (2003) or other engineering recommendations. 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), ground water elevation is even with mean sea level; the rate of flow could not be calculated. Given that the ground elevation of the Site is 55 feet above sea level, based on the County ground water maps the depth to ground water below the Site is estimated to be approximately 55 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). A total of 22 sampling events were identified at wells within three-quarters of a mile of the Site. Of these, 14 events included sampling for DBCP; it was detected in 11 of the events at concentrations ranging from 0.12 to 6.7 µg/L. A total of 11 sampling events included nitrate; it was detected in 10 of the events at concentrations ranging from 2.6 to 56.0 mg/L. The Maximum Contaminant Level (MCL) set by the US EPA for nitrate as NO3 is 45 mg/L. The MCL for DBCP is 0.2 µg/L. Based on the data consulted, it appears that much of the ground water in the vicinity of the Site contains DBCP in excess of the MCL. The data indicate that nitrate is present in the area, but is encountered for the most part at levels below the MCL. LOGE 1422 Page 3