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30 August 2019 AdvancedGeo AGE Project No. 19-4819 Environmental Page 10 of 15 8.0. GROUNDWATER ANALYSIS The subject property is supplied with potable water by the onsite domestic water well located in the northwest quadrant of the site (Figure 2). A groundwater sample was collected from the well and analyzed for nitrates as part of this study. 8.1. DESCRIPTION OF LOCAL GROUNDWATER According to the San Joaquin County Flood Control and Water Conservation District's Lines of Equal Depth to Groundwater Fall 2018 and the DWR Water Data Library, depth to groundwater at the site is approximately 20 to 30 feet bsg. Groundwater flow direction locally appears to be toward the north. Groundwater was not encountered in the 42-inch deep percolation test hole on 22 August 2019. 8.2. EXISTING OR POTENTIAL GROUNDWATER CONTAMINATION The immediately adjacent and outlying land use for the parcel is residential and agricultural. Potential groundwater contamination can occur from several sources including leaking underground storage tanks, septic systems, agricultural activities, dairies, and stormwater infiltration. A review of the DTSC EnviroStor Database and the Geotracker Web site did not reveal any sites of environmental concern within a half-mile radius of the site. Based on the information reviewed, 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 The existing water supply well at 17454 Von Sosten Road (site) conforms to DWR and EHD standards and is used to supply the subject property with a domestic water source. 9.0. IMPACT OF NITRATE TO GROUNDWATER Due to the residential use of the property and the potential for nitrate leaching into the groundwater from the existing and proposed septic systems, a nitrate loading analysis for the future use of the septic systems 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 and residential lands which might provide a nitrate source. There are several residences within 1,000-feet of the site.