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KLEINFELDER accordance with SJCEHD criteria. Approximately 2 inches of fine gravel was placed at the bottom of each test hole. The percolation tests were presoaked with at least 12 inches of water on May 30, 2005. And the tests were initially performed on May 31, 2005, in accordance with accepted guidelines using clear potable water. The testing was done in warm and sunny conditions. The approximate depth of each percolation test below existing site grade is shown on the following table. The holes did not exhibit sloughing or caving. From a fixed reference point, a marked location on the side of PVC pipe inserted into each hole, the drop in water levels were measured in approximate 30-minute intervals for four hours, refilling as necessary to maintain the prescribed amount of water over the gravel (SJCEHD Procedure #2). As specified, the last two 30-minute readings were recorded under the observation of a representative from the SJCEHD and were used to calculate the percolation rate in minutes per inch. These initial shallow and deep test holes did not exhibit adequate percolation. Our drill rig returned to the site on June 3, 2005 and installed an additional deep percolation test hole in each lot using 6- inch diameter auger. The test holes were prepared as described above. The test holes were presoaked on June 5, 2005, with at least 12 inches of water. These percolation tests were performed under sunny and clear skies on June 6, 2005 in the same manner as described above. Details of each test can be found on the attached percolation test sheets. Depth of Test Hole Percolation Rate Lot Number Date of Test feet mindinch) 16 May 31, 2005 3.8 250.0 June 6, 2005 .2 25.0 May 31, 2005 3.4 125.0 17 5.1 Did Not Percolate June 6, 2005 24.7 20.8 The results of our percolation tests indicate that a suitable soil percolation stratum exists at depths of approximately 24 to 25 feet below the existing ground surface. A suitable soil condition for tests deeper than 3% feet is defined as a stratum capable of percolating water at a rate of 30 min/inch or faster. Based on these results, conventional septic tank/leach trench sewage disposal systems designed per SJCEHD criteria should adequately serve the proposed residences constructed on these lots. Seepage pits should extend into the soil strata in which the passing percolation rates were obtained. Based on our results we do not anticipate a need for engineered systems to be installed at the residential parcels. 57556.G01/ST05R687 June 10,2005 ©2005 Kleinfelder,Inc. Page 4 of 5