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LOGE 2126 Page 11 CONCLUSIONS Based on the method and assumptions described, the result of the nitrate loading estimate indicates that the existing development on the Site has the potential to cause a buildup of nitrates in the aquifer of up to 14.8 mg/L-N, over the drinking water standard of 10 mg/L-N. The depth of ground water based on recent aquifer levels is estimated to be approximately 15 feet below ground surface. The ground-water flow is to the north or northwest at a rate of approximately three to five feet per mile, depending on the season. No wells are located on the Site; no water sample was collected as part of this investigation. The Site is connected to the municipal water supply. Live Oak reviewed maps of water test results for nitrate and DBCP compiled by the San Joaquin County Environmental Health Department (2019). According to the maps reviewed, ground-water concentrations of nitrate within one mile of the Site appear to be below the MCL; DBCP does not appear to be a problem in the area. Based on conservative nature of the nitrate loading calculation and lack of existing nitrate impacts in the area, the actual nitrate impact to the ground water from the proposed development may be less than predicted. Recent San Joaquin County Environmental Health Department policy has been to evaluate each project on a case- by-case basis to determine whether additional measures to mitigate nitrate should be employed. Although Live Oak cannot make engineering recommendations, we are aware that in the past the San Joaquin County Environmental Health Department has allowed the use of an oversized septic tank combined with soil amendments in the leach field area to mitigate nitrate impacts; this option may be worth exploring for the Site should the septic systems require repairs or additions in the future. Finally, it should be noted that the Site and the majority of surrounding properties are connected to the City of Lathrop’s municipal water supply, which receives most of its water from surface water sources (City of Lathrop, 2019). The primary purpose of nitrate loading analysis is to protect drinking water wells from nitrate contamination. Given the lack of receptors in the area, the Site’s calculated nitrate exceedance may be of less concern.