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A review of Application Permits on file with the San Joaquin County Environmental Health Department indicates there have been eight Applications for Repairs/Additions in the one-half mile diameter study area. These applications for modifications to existing systems were for additional drainage(leachlines)and sumps. This can be considered an upper-medium number of Applications considering the low density housing in the area and indicates the soil may eventually develop a biomat severe enough to impede effluent percolation. The closest Well Driller's Log that was on file at the Environmental Health Department was for the well at the Fire Station located 500 feet to the west of Parcel 1. This well log shows varied soil strata of shale,sand and clay down to 200 feet in depth. From a depth of 15 to 48 feet,the soil characteristics are a clay and shale composition according to this well log. This clay layer may have an attenuating influence on the downward migration of nitrate molecules. [3] SOIL PROFILE AND PERCOLATION TESTING A shallow percolation test(46 inches)was performed on Parcel 1 on September 22, 1999. The perc test procedure was conducted according to San Joaquin County Department of Environmental Health regulations. No perc test was done on the Designated Remainder in compliance with County requirements. The test location was directly west of the house and is illustrated on the Tentative Map. The Field Test Data Sheet with the perc test results can be found in the Appendix. The perc test boring was composed of a silty, fine-to-medium sand(SM-SP) down to 46 inches. This is the depth where effluent percolation would normally take place from a leachline. No hardpan or other type of restrictive layer was encountered in the boring. The final perc rate obtained after the one-hour test period was 1.4 minutes per inch(min/in). This percolation rate can be considered extremely fast. Although there was some variability in the perc rate over the one-hour test period,it appears that the soil has an enormous capacity to accept water due to the sandy soil structure. The groundwater is approximately 35 feet deep in this locale; therefore, sumps may be installed in this area, but are generally not necessary for residential structures. A 12-foot hand boring was completed in the area of the perc test location. The attached Log of Boring illustrates the subsurface soil composition. There was a thin cemented silts hardpan located at eight feet below existing grade. Although permeability may be impeded to a slight extent at this depth,the hardpan layer was not significant enough to impede percolation. [4] LOCAL GROUNDWATER AND SURFACE WATER INFORMATION The static water table depth, or the zone of saturation was determined by the 1997 "Lines of Equal Depth" published by the San Joaquin County Flood Control District. It is highly unlikely there is a perched water table condition under the subject property at a higher elevation than the static water level. There is no potential for future septic impact to any surface waters,namely irrigation or other conduit water,providing applicable distance requirements are followed. The groundwater directional flow appears to be north-northeast. As observed on the USGS map which was photo-inspected in vafi�y Ag research