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23 October 2019 AdvancedGeo AGE Project No. 19-4881 Ernviror-inientaI Page 10 of 15 centimeter (mmhos/cm). Sands in the Manteca fine sandy loam complex typically have the same chemical properties between surface grade and 60 inches bsg. 7.2. MASS TRANSPORT PROPERTIES OF UNDERLYING SITE SOILS The percolation test and dominant soil type at the site indicates that the soils are semi- permeable to permeable and have low water storage. These soils will allow moderate infiltration of water through the surface soils. The longer the effluent remains near the surface, the more treatment is enhanced due to natural processes within the soil. If the permeable soils exist to the depth of the groundwater table, it is possible that surface contaminants may be transported fairly rapidly. 8.0. GROUNDWATER ANALYSIS The subject property is supplied with potable water by the onsite domestic water well located to the southwest of the existing residence (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 25 bsg. Groundwater flow direction locally appears to be toward the southwest. Groundwater was not encountered in the 39- inch deep percolation test hole on 10 October 2019. 8.2. EXISTING OR POTENTIAL GROUNDWATER CONTAMINATION The immediately adjacent and outlying land use for the parcel is residential, industrial, 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 revealed one (1) LUST site, one (1) above ground storage tank fuel release site, and one (1) pesticide- impacted soil site within a 0.5-mile of the subject property. However, all three sites have been closed for over 15 years. Based on the status of the investigations and their distance and direction from the subject property, the closed investigations should not impact the subject property. The review did not reveal any other sites of environmental concern within a 0.5-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.