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reasonably be required to remove this contaminant should it occur in drinking water. The Maximum Contaminant Level Goal (MCLG) for DBCP is zero. I Profile and Geologic Information The Site is depicted on the Geologic map of the San Francisco -San Jose quadrangle, California (Wagner et. al, 1991). The Site is depicted within a map unit of the Modesto formation (Plate 8). The surface and near surface soils located at the Site are reported by the USDA Web Soil Survey to be composed of Hollenbeck silty clay (Plate 9) (USDA, 2020). The table below presents some selected properties of this soil: Table 1. Selected Properties of On -Site Soils (USDA, 1992) Soil Name Depth Unified Soil Salinity Soil Perme- Septic tank and Map Reaction ability absorption Symbol (in) Classification mmhos/cm pH (in/hr) fields Hollenbeck 0-10 Silty clay; CH, CL <2 6.6-8.4 0.06-0.2 Severe: silty clay, 0- 10-37 Clay, silty clay; CH, CL <2 6.6-8.4 0.06-02 peres slowly 2% slopes, 37-42 Silty clay loam, clay <2 6.6-8.4 0.2-0.6 173 loam; CL 42-60 Cemented --- --- --- Note: The table descriptions do not necessarily reflect site-specific soil properties. See description of the map unit for composition and behavior characteristics of the map unit. Soil Borings On September 1, 2021, Live Oak excavated a shallow soil boring near the proposed septic disposal area of the Site for the purpose of conducting a percolation test. The boring was four inches in diameter, 3.25 feet deep, and was excavated by hand auger (Table 2). The location of the boring is indicated on Plate 10. The soil in the boring was similar to that described by the Soil Survey. Clay was encountered to 3.0 feet below ground surface, followed by sandy clay to the full depth of the hole. The soil log is presented on Plate 11. Discussion of Soil Lithology Based on the soil observed in the boring, there appears to be some potential for percolation in the shallow soil zone at the test location. Sandy soils generally have a much greater potential for percolation than fine-grained or cemented soils. However, a percolation test is the only accepted method for determining the suitability of the soils LOGE 2144 Page 5