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13 August 2021 AdvancedGeo Project No. 21-6530 AnfmployeeawoedCompony Page 8 of 14. 6.6. POTENTIAL PROBLEMS PREDICTED On site soils within the shallow percolation test hole demonstrated an adequate percolation rate. 6.7. PERCOLATION TEST FINDINGS The shallow percolation test performed provided a satisfactory percolation test rate. The percolation rate of 5.68 minutes per inch was calculated from data collected during the four-hour percolation test; the final reading over the four-hour period was used to calculate the percolation rate. The use of the proposed septic system should follow the San Joaquin County On-site Wastewater Treatment Standards. 7.0. CHEMICAL AND PHYSICAL PROPERTIES OF SOIL Soil chemical properties were supplied by regionally sourced material for the surrounding area. 7.1. CHEMICAL AND PHYSICAL PROPERTIES OF SITE SOILS The dominant soil composition in the general area of the property was inferred from information provided by the United States Department of Agriculture's Soil Geographic Database (USDASGD). The USDASGD soil survey indicates the soil type for the property is predominantly composed of Galt clay having 0 to 1 percent slopes (#160). The Galt clay is composed of alluvium derived from mixed rock sources. Soils are described as somewhat poorly drained, with a moderately low permeability, and salinity ranging from 0.2 to 0.5 millimhos per centimeter (mmhos/cm). The Galt clay typically features clay from 0 to 32 inches bsg and cemented soils from 32 to 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 and have moderate 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.