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CONCLUSIONS AND RECOMMENDATIONS In summary, the soil conditions examined on each parcel were found to be suitable for a standard septic system. Satisfactory soil percolation rates of 6.58 min/in (Parcel 1), 8.93 min/in (Parcel 2), 9.26 min/in (Parcel 3), and 7.14 min/in (Parcel 4) were observed in the deep (6- to 13-foot) soil zones at the test locations. The soils in the test locations were found to be clay, silty sand, and sand. The depth of ground water based on recent aquifer levels is approximately 85 to 110 feet below ground surface. Ground water flows to the northwest in the area at a rate of approximately 15 feet per mile. Because of the percolation rates between 5.0 and 30.0 min/in encountered in the deep test holes, the San Joaquin County Environmental Health Department will require an eight-foot separation from the bottom of the dispersal system to ground water. Based on the anticipated depth to ground water, no modifications to standard septic systems should be required. No water sample was collected as part of this investigation. Based on maps reviewed, it does not appear that nitrate or DBCP levels exceed the MCL in nearby wells within a mile of the Site. Based on the methods and assumptions described, the nitrate loading calculation indicates that the use of on-site septic tanks and drain field systems for two houses with up to eight total bedrooms on the Site has the potential to cause a buildup of nitrate in the aquifer up to 1.3 mg/L, well below the MCL of 10 mg/L-N. No construction is anticipated. Any future septic system construction should utilize leach lines and seepage pits and should follow the San Joaquin County On-Site Wastewater Treatment Systems Standards (2017) where applicable. Based on the results of the nitrate loading analysis, no nitrate mitigation is recommended. LOGE 20-54 Page 14