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The water analysis above for nitrate concentrations reveals a comparatively low nitrate ?moking nentration average of 9.3 ppm as NO3. The Maximum Contaminant Level (MCL) for NO3 in water is 45 ppm, therefore, the concentration is approximately one-fifth the MCL, on erage. The construction details and depth of this domestic well were unavailable, but it is assumed to be comparatively deep. The test results follow an interesting trend of rising through the 1980s and declining through the 1990s. The agrichemicals DBCP and EDB were not required to be tested, in accordance with the Environmental Health Department. In addition to the drinking water investigation for nitrate concentrations, two water table samples were obtained from the backhoe test pits referenced above. The water table depth encountered in the downgradient test pit was measured at 14 feet below grade. The test results found on the WATER ANALYSIS REPORT reference this downgradient sample identification as "DN-14." Test results for this sample reveal a nitrate (as NO3)to be 13 ppm NO3. The upgradient sample was retrieved from 10 feet below grade and is denoted as "UP-10." Nitrate test results for this sample indicate a concentration f 13 ppm The depths to the water table and nitrate concentrations were not expected. It was thought that the depth to the saturated zone would be roughly equivalent between the two test pits given the fact that there has to be a large volume of effluent recharge from the filter beds. However, the water table in the downgradient test pit was four feet deeper than the upgradient test pit. Additionally, it was also thought that the downgradient nitrate concentration would be higher than the upgradient, also due to influence from effluent recharge. B1�tr the d�wngradien ^te concentration was 2.4 times lower than the upgradient. Also noted is the fact that both samples are below the MCL for nitrate. CONCLUSIONS The results of the percolation test suggests acceptable percolation of septic effluent at the typical leachline depth of 42 inches. This shallow test depth also reveals there will be sufficient distance for "treatment" of septic effluent,which includes the destruction of bacteria and viruses before it encounters the groundwater table. It was also evident that percolative capacity did not decrease with soil saturation, over the four-hour test. The hydraulic conductivity test indicates the permeability of the surface soils did decrease with soil saturation by almost a factor of one-half over the four-hour test period. Test results indicate that the surface soils do have the capacity to accept effluent; however, continued application over time does decline with soil saturation. LL Page -5- cy consu�xing