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a June 27, 2005 NOA Project Number: E05087A Standards where applicable. The EHD typically has concerns about groundwater contamination when percolation rates are faster than 5 minutes per inch. Due to the rapid percolation rates,we wo recommen uicreasmg the septic tank size to one larger than is require Me On-Site Wastewater Disposal Standards to increase retention time in the tank and improve denitrification. In addition,we would recommend using a filter bed with an addition of four to six inches of compost peat to reduce the percolation rate and improve the treatment of,the waste water. Refer to the attached Nitrate Loading Study for any additional recommendations for the project. 7.0 CONCLUSIONS In summary, satisfactory percolation rates of the soil were achieved in the proposed septic disposal areas of all the Parcels. The soils of the proposed Parcels appear suitable for a standard septic system. However, our office recommends that the new septic systems use a larger septic tank size and a modified filter bed to improve the treatment of the waste water due to the sandy soilds and rapid percolation rate. No ground water was encountered in any of the borings drilled on the property. The depth to ground water was found to be approximately 60-70 feet below the ground surface for the period of Fall 1998 and Spring 1999 based on the San Joaquin County Ground Water Maps. The water well on the adjacent property was tested for nitrate and DBCP. DBCP was not detected + in the water sample. The nitrate concentration in ground water was found to be 7.46 mg/L-NO3, which is below maximum contaminant drinking water limit of 45 mg/L-NO3. LIMITATIONS N $.0 LIM O S The conclusions of this report are based on the information provided regarding the existing and proposed development, the use of the subject property, and the site conditions as they existed at the time we excavated our test holes and performed the percolation tests. It was assumed that the test rtholes and percolation test results are representative of the subsurface conditions in the general area. Our professional services were performed, our findings obtained, and our conclusions proposed in accordance with generally accepted engineering principles and practices. This warranty is in lieu of all other warranties either expressed or implied. Test findings and statements of professional opinion do not constitute a guarantee or warranty, expressed or implied. 8.1 Signatures The signatures of the environmental professionals involved in the preparation of this report can be found on the cover sheet at the front of this package. 10