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KLEINEELDER procedure calls for first placing about 2 inches of fine gravel at the bottom of the borehole. The hole is then pre-soaked with a minimum of 12 inches of water at least 24 hours prior to performing the test. The percolation tests were started at 12:00 noon on September 10, 2003, under sunny and warm weather, in accordance with accepted guidelines using clear potable water. All holes were still intact with no significant sloughing or caving noted. The approximate depth of each percolation test below existing site grade is shown on the following table. The correct depth for the shallow percolation test is 3.6 feet, not 2.6 feet as noted on the percolation test sheet. The holes were dry prior to testing. From a fixed reference point (a marked location on the side of PVC pipe inserted into the hole), the drop in water level is measured in approximately 30-minute intervals for four hours, refilling as necessary to maintain the prescribed amount of water over the gravel (Procedure #2). Under the observation of a representative from the SJCEHD, the last 30-minute reading of the four-hour period is recorded and used to calculate the percolation rate in minutes per inch. The estimated percolation rates are summarized below. A copy of our field percolation test results signed by a representative from SJCEHD is attached. Details of each test can be found on the percolation test sheet. Test Number Depth, feet Percolation Rate minute/inch P-1 3.6 36 17.4 7 A note by Mr. Ray Borges, representative of the SJCEHD, at the bottom of the percolation test sheet states "deep perc added too much water;" however, in a telephone conversation with Mr. Borges on September 11, 2003, it was determined that the amount of water in the deeper percolation test was indeed appropriate for that test. Based on the passing percolation tests and soil types encountered, we do not predict any problems with the proposed septic system or foresee the need for an engineered or alternative septic system. We do not anticipate any geotechnical restrictions on future type, size, or location of any additional leach fields on the subject property. NITRATE LOADING CALCULATIONS Per SJCEHD requirements, the following summarizes our nitrate loading calculations for the proposed leach fields. The state drinking water standard for nitrate is 45 milligrams per liter (NO3) and 10 mg/1 as Nitrogen (I) in groundwater. In our evaluation of nitrate loading, we have used the Hantzsche mass balance equation (source: Predicting Groundwater Nitrate-Nitrogen Impacts, Hantzsche and Finnemore (1992)), which is presented below with an explanation for each factor and the value used in our study. The selection of parameters was based on previous studies and investigations performed by our firm and others, San Joaquin County Sewage Standards, communication with Mr. Mike Huggins with SJCEHD, and information provided in a report dated March 19, 1997 prepared by the Questa Engineering Corporation and authored by Mr. Hantzsche for a development in the Stockton area. 35228.G01/ST03R1508 October 14,2003 ©2003 Kleinfelder,Inc. Page 4 of 6