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No contribution from any irrigation or soil amendment is considered for the Hantzsche/Finnemore method. It is assumed that any irrigation or soil amendments would be applied at close to agronomic rates for a net balance of plant irrigation and nutrients. Percolating_Recharge Waters One of the most determinant factors in the Hantzsche and Finnemore equation is the rate of recharge from percolating waters, which mix with the downward-percolating effluent generated by on-site septic systems. In the original Hantzsche and Finnemore paper, only "average recharge rate of rainfall" was considered. For the Chico area, Hantzsche and Finnemore present an average rainfall of 22.5 inches per year and an estimated recharge of 16.8 inches per year. Based on San Joaquin County Environmental Health Department policy (personal communication, March 18, 2019), the recharge input for the Hantzsche and Finnemore equation should be derived from average monthly precipitation of rainfall and evapotranspiration rates for the area; the data should be obtained from the California Irrigation Management Information System (CIMIS), preferably from stations located within San Joaquin County. Recharge is calculated by first determining whether the average monthly precipitation exceeds average monthly potential evapotranspiration. If so, then the difference is the percolating recharge water into the aquifer. Runoff and stream infiltration drainage are not factored into the calculation. This approach likely under-estimates recharge to the aquifer and, consequently, over-estimates nitrate loading. For the project Site, the local percolation and evapotranspiration rates are presented in Plates 13 and 14. The Site is located between the CIMIS Stations at Holt (station 248) and Staten Island (station 242); taking both stations into account will yield a value more representative of the Morada area. During the past five-year period, data from the Holt station were only available for 2017 and 2018; based on the calculation shown, the estimated rate of recharge from percolating waters for the Holt station is determined to be 3.72 inches. A statistical error of 25 percent is associated with this value, as calculated on Plate 13. Data for the Staten Island station were available for the past three years; based on the calculation shown, the estimated rate of recharge from percolating waters for the Staten Island station is determined to be 12.60 inches (Plate 14). A statistical error of 49 percent is associated with this value. The two stations are then averaged, for a regional deep percolation value of 8.16 inches. The nitrate concentration of the recharge waters was estimated to be 1 mg/L-N (Hantzsche and Finnemore). LOGE 1916 Page 7