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SILVERA PROPERTY, SOIL SUITABILITY STUDY Page No. 4 The percolation tests were performed in an 8 inch diameter test hole. The depth of the test was 36 inches for PT-1 (Parcel #1) and 40 inches for PT-2 (Remainder Parcel). A 3 inch diameter perforated pipe measuring device was placed in the test holes and backfilled with 3/4 inch gravel. The holes were filled with water 24 hours prior to running the tests. The last ten minutes of the test readings were witnessed by a San Joaquin County health official and the test data obtained is contained in the Appendix. The results of the tests indicate that PT-1 had a percolation rate of 2.0 min./inch and PT-2 had a percolation rate of 9.0 min./inch. VII CONCLUSION Due to the variations in soil profiles and ground surface and ground water elevations, certain areas of the subject property are favorable for septic system usage and certain areas are less favorable. Consequently each proposed parcel will be summarized separately. Remainder Parcel This parcel currently has the Silvera residence located in the NE portion of it. The soils encountered in the test pit excavated adjacent to the existing leach field (TP-4) showed a clayey fine sand stratum from 3.0 to 5.0 feet. The percolation test ran at this location, which penetrated this stratum, indicated a percolation rate of 9.0 min/inch. Consequently it is our opinion that this area, as also indicated by the history of the system, appears favorable for continued use of the existing septic system. Due to the high ground water (5.0 feet), however, the surface stratums could easily become saturated in heavy rains, greatly reducing the effectiveness of the leach field. This factor should be taken into consideration in the design of a replacement system should one become necessary. Also as a result of the high ground water, its quality as affected by the septic system is a concern. For this reason a sample of ground water was obtained and tested for the presence of nitrates. The test results show the nitrate level well below the MCL. In addition a clay stratum existed from 6.0 to 8.5 feet that would greatly reduce the migration of any nitrates from the leach field into the underlying water table. Consequently, it is our opinion that continued use or replacement (if required in the future) of the septic system should not adversely affect the quality of groundwater in the area. Parcel #1 Although there is no proposed development of the parcel at this time, a potential future homesite would most likely be located in the SW corner of ER o ssoc\