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— March 29,2001 _ Job Number: LGO1-031 Page 7 One percolation test was performed adjacent to the exploratory boring in the proposed septic leach field. The percolation test hole was set to a depth of 17 feet in a soil consisting of brown fine sand with some silt. The percolation test casing was a 2-inch PVC pipe with holes drilled on the bottom. Two inches of"pea gravel"was placed in the bottom of hole,the casing was installed, and several feet of"pea gravel"was backfilled in the annular space. A preliminary percolation test was conducted on February 7, 2001 to determine if a 1 hour or 4 hour test was — required. Based on a preliminary test, a one(1) hour test would be acceptable. The percolation hole was pre-soaked 24-hours prior to the actual one-hour percolation test. A one-hour percolation test was conducted on February 8, 2001 in accordance with the requirements of San Joaquin County Environmental Health Division. The entire test was observed by Ted Norgard, R.E.H.S. of that office. The result of the percolation test indicates a satisfactory percolation rate of 1.3 min/in was achieved. VII. CONCLUSIONS AND RECOMMENDATIONS In conclusion, a satisfactory percolation rate was achieved for the Parcel 1. The — percolation rate was measured at 1.30 min/inch at a depth of 17 feet. No test was required for Parcel 2. The ground water collected from the on-site well was tested. Nitrogen was detected at a concentration of 3.3 mg/L as NO3 which is well below the EPA maximum contaminate level of 45 mg/L as NO3. DPCP was not detected in the ground water sample. No ground water was encountered in the borings and the depth to ground water according to a recent San Joaquin County Flood Control and Water Conservation District ground-water map is about 120 to 127 feet below the ground surface at the site. Based on the results of this study, our office has found the soils to be suitable for a septic system and leach lines and seepage pits for the proposed Parcel 1. We believe that due to the proposed use and size of the parcel, the use of the septic system will not negatively impact the ground water quality of the area. We recommend that the design and installation of the septic system follow the requirements established by the San Joaquin County Environmental Health Division. i VIII. 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 hole and performed the percolation test. It was > n = W O - ♦sso�.