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area utilize leach lines with seepage pits; one permit indicated a system with leach lines only. The septic permits can be found in Appendix 4 of this report. Expected On-Site Maximum Septic Tank Usage Maximum expected septic usage on the Site would be from the exiting residences and potential future second unit dwellings on each 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 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 60 to 63 feet below mean sea level, depending on the season. The ground-water flow is to the east at a rate of approximately six feet per mile for fall 2016, no rate could be calculated for spring 2016. Given that the ground elevation of the Site is approximately 45 feet above sea level, based on the County ground water maps the depth to ground w ter below the Site is`A'•�4..� estimated to range from 105 to 108 feet. ,`"'`"�llJ 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 one-half mile of the subject Site. All four wells had all been tested for DBCP; it was only detected in one sample, at a concentration of 0.99 ug/L. All four wells had been tested for nitrate; it was detected in three of the wells at concentrations of 8.0 to 14.0 mg/L-NO3. The Maximum Contaminant Level (MCL) set by the US EPA for nitrate as NO3 is 45 mg/L (10 mg/L-N). The MCL for DBCP is 0.2 ug/L. On-Site Wells One domestic well is located on the Site. Three well permits were identified for the Site at the San Joaquin County Environmental Health Department: LOGE 1816 Page 3