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[4] SOIL PROFILE AND PERCOLATION TESTING Soil profile information from the drilling of domestic wells, and the installation of septic systems in the area of the subject site were obtained from the San Joaquin Department of Environmental Health. The Well Logs illustrate a soil structure of primarily clay lenses, sand and shale. There is a hardpan layer approximately two to three feet under the subject site. The exploratory Log of Boring performed on the subject parcel illustrates the soil structure under the proposed leaching area, and it accompanies our percolation test data. The percolation tests conducted by Quality Control Inspection, Inc. were performed in accordance with San Joaquin Environmental Health Department regulations. The test results can be found in the Appendix. The percolation rate, as tested for the deep test boring (8 ft, 8 in) , was calculated to be 1. 6 minutes per inch. The predominate soil type encountered during the drilling to conduct the percolation tests was a sand formation found under the surface (2-3 feet) hardpan layer. This sandy soil structure produces a relatively fast percolation rate for sewage effluent as evidenced by the above percolation rate. [5] LOCAL GROUNDWATER INFORMATION The 1990 "Lines of Equal Depth of Water in Wells" map produced by the San Joaquin County Flood Control and Water Conservation District indicates that the static water level is located at approximately 80 feet in the area of the subject parcel. An exploratory test hole was drilled in the lowest point of the two parcels to a depth of 25 feet, revealing no indication of moist soil or any past history of a water table at this depth. The groundwater flow according to the District maps appears to be towards the northwest, although many factors can influence this general groundwater directional flow. 3 .e QWlity 10ntrol Inspection