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11 October 2019 AGE Project No. 19-4782 Page 10 of 14 8.1. DESCRIPTION OF LOCAL GROUNDWATER The San Joaquin County Flood Control and Water Conservation District’s Lines of Equal Depth to Groundwater Fall 2018 indicates the depth to groundwater is approximately 60 feet bsg. Groundwater flow direction locally appears to be toward the north. Groundwater was not encountered in the 40-inch deep percolation test hole on 18 July 2019. 8.2. EXISTING OR POTENTIAL GROUNDWATER CONTAMINATION The immediately adjacent and outlying land use from the subject property is residential, commercial, and agricultural. There are potential groundwater contamination issues associated with agricultural uses and septic systems. A review of the California DTSC EnviroStor Database and the Geotracker Web site revealed two LUST sites within a one- mile radius of the site. However, both sites have been closed for over 10 years. The sites were located approximately 500 feet and 2,500 feet from the subject property. Based on information reviewed on the Geotracker Web site, residual petroleum hydrocarbon contamination was not left remaining in place at either site. There is no existing or known groundwater contamination at the site and the potential for groundwater contamination is de minimis. 8.3. CURRENT AND FUTURE USE OF GROUNDWATER AT THE SITE In accordance with San Joaquin County Community Development Title, Section (9- 1115.8(b)) provision of water to a residence from an offsite private, domestic water well located on a separate recorded parcel is prohibited. Therefore, an alternate source of potable water will need to be located or a new domestic water well will need to be installed on the subject property to provide water to the planned development. The existing water supply well at 17699 ST RT 120 cannot be used. 9.0. IMPACT OF NITRATE TO GROUNDWATER Due to the proposed residential use of the property and the potential for nitrate leaching into the groundwater from the proposed septic system, a nitrate loading analysis for the future use of the septic system is required by the EHD. 9.1. CURRENT OFF-SITE SOURCES OF NITRATE Septic systems and agriculture are sources of nitrates in the area of the site. The property is bordered by agricultural, commercial and residential lands which might provide a nitrate source. There are several residences within 1,000-feet of the site.