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08/01-'01 WED 16:18 FAX PHS/EHD 2003 File No. 20-3644-01 KLEiNFELOER June 30, 1992 were tested on June 18 and 19 , 1992, and two lots were tested on June 22 , 1992 . As per San Joaquin County guidelines, the tests were performed for a period of four hours. The last 30 minutes of each test were observed by the County sanitarian and were used to calculate the percolation rates. In order to use standard leach lines, the County requires a percolation rate of 60 minutes per inch, or faster, at the 3- foot depth. In order to use sump pits, the County requires a soil strata with a percolation rate of 30 minutes per inch, or faster, be located. Based on the above criteria, two 3-foot deep, seven approximate 8- to 10-foot deep, and four approximate 14- to 15-foot deep tests produced passing percolation rates. A passing test was obtained on seven of the eight lots tested. Table I at the end of this report presents the percolation rates and depths for each lot tested. The County approved percolation test sheets are also included with this report. On the basis of the test results presented in Table I, it appears that the most suitable soil strata with percolation rates meeting County standards is at the approximate 8- to 10-foot depth. Although no passing test was obtained on Lot 10, based on the test results and our experience, it is our opinion that a passing test will likely be obtained at the approximate S- to 10- foot depth at another location on lot 10. We note that prior to final approval for construction, the County will require a passing percolation test be obtained at each lot. We will be happy to prepare a proposal for performing the additional percolation testing. IT "The depth and gradient of the water table; " During our residence surveys on June 22 , 1992, we were not able to measure groundwater in the domestic wells. The regional groundwater depth map published by the San Joaquin County Flood Control and Water Conservation District, Plate II, indicates the depth to groundwater in the site area was approximately 80 feet in spring 1991. Based on the groundwater map showing lines of equal elevation of groundwater, plate III, we conclude that the main groundwater gradient is in the approximate north-northwest direction. ITEM C-5: "other information as required by the San Joaquin Local Health DistrivL to determine the cumulativa affect. of the existing and the proposed development on groundwater contamination;" Copyright 1992 Kleinfelder, irc. page 3 of 4