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July 25, 2006 NOA Project Number:E0514113 Page 3 Discussion of Percolation Test Results The soils within the sewage disposal areas of the site have demonstrated a satisfactory percolation rate in accordance with the requirements of the EHD for the use of a standard septic system.The percolation test results are listed below. Summary of Percolation Tests. Test No., Percolation Percolation Rate Test Comment Date Tested Test Depth(ft) (minutes/inch) Duration (see notes) P-1 Shallow 3.2 83.3 4 hours Failing percolation rate P-1 Deep 12.18 4.55 4 hours Satisfactory percolation rate P-2 Shallow 3.12 35.71 4 hours Satisfactory percolation rate P-2 Deep 11.62 4.23 4 hours Satisfactory percolation rate P-3 Shallow 3.12 31.25 4 hours Satisfactory percolation rate P-3 Deep 15.98 20.83 4 hours SatisfactoMZErcolation rate Note: A satisfactory percolation rate for a"shallow"test is less than or equal to 60 minutes per inch.A satisfactory percolation rate for a"deep"test is less than or equal to 30 minutes per inch. Discussion of Septic System Sizing Septic System Construction should follow the San Joaquin County On-Site Wastewater Disposal Standards where applicable. CONCLUSIONS In summary,a satisfactory percolation rate of the soil was achieved in the proposed septic disposal area on the Site. The site appears to be suitable for a standard septic system using leach lines and seepage pits in accordance with EHD requirements. No ground water was encountered in any of the borings drilled on the property. Groundwater is recorded to be between 60 and 70 feet below ground surface. The on-site water well was tested for nitrate and DBCP. DBCP was non-detectable, and nitrate concentration in ground water was found to be 61.7 mg/L-NO„which is above the maximum contaminant drinking water limit of 45 mg/L- NO3. We recommend the well not be use for drinking water since the water quality test indicates levels of Nitrate above the MCL for drinking water.We recommend discussing well repair options for elevated nitrate with EHD. Due to the depth to groundwater and the soils present,we do not believe the use of the septic system will adversely impact groundwater.