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KLEINFELDER Control and Water Conservation District show groundwater levels in the project area ranging from about 50 to 85 feet below ground surface from Spring 1981 to Spring 1999. SEPTIC PERMITS AND PERFORMANCE We are unaware as to the performance or number of the existing septic systems on site. On April 28, 2003, an employee of the San Joaquin County Environmental Health Department (EHD) pulled the permits on file for the subject property and those parcels adjacent to the subject property. Only one septic permit was on file for an adjacent property. Permit No. 3092 was issued in 1994 and was for 9047 East First Street. This permit is for a septic tank and two 48- inch diameter by 25-foot deep seepage pits. The permit was for a repair/addition. FIELD EXPLORATIONS AND TESTING The subsurface conditions at the site were explored on May 1, 2003, by drilling one boring to a depth of approximately 24 feet below existing site grade. The boring was used as a percolation test hole. In addition, a total of seven percolation borings were drilled among the three proposed sewage disposal areas to depths between approximately 3.3 and 14 feet below existing grade. The borings were drilled using a Simco 2400 truck-mounted drill rig equipped with 6-inch O.D. solid-stem auger. Theapprox a locations of the percolation tests are described below and are also shown on Plate 1.7 " Location Number Location P-1 21' east, 35' south of northwest property comer P-2 40' east, 70' north of southwest property corner P-3 110' west, 70' north of southeast property corner Based on our findings, the subsurface soils encountered consisted of interbedded layers of light brown to light gray-brown sandy silts and silty and relatively `clean" sands to the depths explored. The percolation tests were performed on May 2, 2003, in accordance with accepted guidelines using clear potable water. The procedure calls for first placing about 2 inches of fine gravel at the bottom of the borehole. The hole is then pre-soaked with water at least 24 hours prior to performing the test. The shallow tests were performed by adding about 6 inches of water above the gravel in the hole. The deeper tests were performed by adding up to about 1.5 feet of water above the gravel. From a fixed reference point, 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. Under the observation of a sanitarian from the EHD, the last 30-minute reading of the four-hour period is recorded and used to calculate the 29556.GOI/S7'03R877 lune 18,2003 ©2003 Kleinfelder,Inc. Page 2 of 4