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kn KLEINFELDER v 2. PRESENT AND PAST USE To the best of our knowledge the property is and has historically been used as agricultural or undeveloped land. No other uses are known. 3. SEPTIC PERMITS AND PERFORMANCE A representative of our firm searched the SJCEHD files to identify septic permits at parcels in the project vicinity. There were no SJCEHD septic permits on file for the subject parcel. Thirteen permits were reviewed for nine parcels located adjacent to or near the subject property. These permits were for new installations as well as repairs/additions to existing septic systems. Each of the permitted sewage disposal systems were for conventional septic/leach field systems with 25-foot deep seepage pits. A summary of the permit information is presented on Plate 2, and copies of the permits are attached. i 4. GROUNDWATER Lines of Equal Depth to Groundwater contour maps published in groundwater reports by the San Joaquin County Flood Control and Water Conservation District (1981 to 1999) show groundwater levels in the project area ranging from about 105 to 140 feet below ground surface. Based on Lines of Equal Elevation of Groundwater contour maps, the general _ groundwater gradient in the project area is generally from south to north. Local gradient variations may occur due to well usage. At the time of our investigation, water was encountered in our profile boring B-2 at a depth of about 12 feet below the existing ground surface. Groundwater or seepage was not encountered at the time of drilling in profile boring B-1. As described in Section 6 of this report, water levels rose through our testing period in the deeper test holes on March 19, 2004. Based on our experience in the project area, as well as the published groundwater data, it is our professional opinion that the water encountered was a perched groundwater condition created by irrigation — of nearby agricultural fields. On September 21, 2004, a representative of our firm obtained samples of groundwater using clean procedures from the head of the domestic well located near the residence. A permit for the well was not on file with SJCEHD, and details of the well construction are not known to us at this time. The samples were delivered to the laboratory on ice that same day using chain-of- custody procedures for DBCP and nitrate (N) testing. The results of the analysis indicate a nitrate (N) concentration of 6.3 mg/1 and that DBCP was not present in detectable amounts. This nitrate concentration is below the state drinking water standard. Copies of the test results and the chain-of-custody are attached. October 15,2004 42270.G01/ST041383 Page 2 of 6 ©2004 Kleinfelder, Inc.