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October 23, 2009 Page 8 of 10 Our Project Number: LGS0090518 • Utilize standard filter bed system design with the following exceptions. • Minimum Septic Tank Sizes 2 bedroom — 1200 3 bedroom — 1600 4 bedroom — 2000 5 bedroom — 2400 6 bedroom — 3200 7 bedrooms and above will require consultation. • Apply 4 inches of compost or peat in the bottom of the filter bed. Utilize gravel drain systems to improve denitrification. 6.0 CONCLUSIONS In summary, percolation rates that meet the minimum EHD standards were achieved in the proposed septic disposal areas of each of the proposed parcels. The-parcels-appear—sWtablefiar P � the use of a standard-septic--system. However, since groundwater is high-within-the-area of the site and varies we recommend the use of mounded septic systems. We t anticipaw-that ANEV• the ground water quality will be negatively impacted primarily due to t sten e.of_peat_and—, ne-grained W's. Furthermore, these conditions are favorable for the removal of nitrate from [b?� sep i sem effluent. Ground water w,ok encountered on parcel 5 at four feet below ground surface. The on-site water well was tested for nitrate and DBCP. DBCP was not detected, and therefore was not above the MCL water limit of 0.2 pg/L.DBCP was detectable. The nitrate concentration in ground water was found to 1.8 mg/L, which is well below the maximum contaminant drinking water limit of 45 mg/L-NO3. 7.0 LIMITATIONS 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 holes and percolation test results are representative of the subsurface conditions in the general area. If there is a substantial lapse of time between the submission of our report and the start of work at the site, or if conditions have changed due to natural causes or construction operations at or adjacent to the site, we urge that our report be reviewed to determine the applicability of the conclusions and recommendations considering the changed conditions and time lapse. This report is applicable only for the project and site studied. This report should not be used after 3 years without the review and update from our office. 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 902 Industrial Way•Lodi,CA 95240•209.367.3701 •Fax 209.369.4228 02009 Nett a Anderson&Associates,Inc