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r7s referenced above, the percolation test results indicate that no effluent percolation will take place in the shallow Tokay soils where there have been truck parking and driving. The more favorable soil structural characteristics of the Kingdon soils reveal excellent percolation and medium hydraulic conductivity where no trucks had been parked or driven over. More importantly, the perc test results illustrate that seepage pits will be the best long-term and high volume effluent management design for the property. The highest anticipated effluent flow over the property has been calculated to be 705 gallons of effluent/day. Given that shallow percolation can be achieved in selected areas, and that deep percolation can be achieved over most of the property, effluent management should not be a problem. It may be a possibility that the existing system for the wood/stucco building will have to be retrofitted with a seepage pit at the end of the existing leachline. There should theoretically be no concern with the bottom of a seepage pit and the highest depth to groundwater. Future design criteria should be based on the permeability of the soil eventually reaching a long term application rate (LTAR) of approximately 0.5 gallons/ft2/day due to biomat formation. It is imperative that a 100%replacement area be designated in the event a repair is required or an additional system installed, and it is also obviously imperative that the area not be parked on or driven over. From the analytical test results on the groundwater underlying the property, it was determined that the drinking water aquifers contain a lower-medium concentration of nitrate. Considering the intense agricultural production in this region, a higher concentration would have been expected. This may be attributed to upper clay layers and possible influence from the Mokelumne River. Previous analytical testing of several wells in the proximity to San Joaquin County rivers has shown significantly lower, or nonexistent nitrate concentrations. Additionally,there is ongoing research at the University of Colorado which suggests there may be denitrification potential within aquifers or saturated zones composed of a fine (vs. a coarse) soil fraction. A comparative nitrogen soil profile was done for this project, which determined that the nitrate concentration through the soil profile is apparently equal, and at a low concentration. Since the vast majority of the property has a thin asphaltic concrete (AC) overlay,this should impede rainwater percolation and the downward migration of nitrate molecules within the soil environment. If the well water supplying the subject parcel serves more than 23 people, for 60 days or more out of any given year, this will cause the existing water system to come under public water supply regulations administered by EHD. Accurate "as-builts" of any septic system installed in the future must be supplied to the EHD and all applicable "distance" requirements must be strictly followed. 13 Chesney Consulting