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LOGE 1848: Ford Construction SSNLS Addendum Page 2 , May 6, 2019 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 in. Quantity of Wastewater For the purpose of the Hantzsche and Finnemore equation, only septic effluent is included in the nitrate loading calculation; no other potential sources of nitrate are considered. The estimated sewage flow rates for various uses are available from a number of references. The value selected was guided by the San Joaquin County On-Site Wastewater Treatment Systems Standards (2017), Crites and Tchobanoglous (1998), and US EPA (1980). The references indicate that 13 gallons for each employee is typical for an office or industrial worker; this rate was used for the facility's employees (Crites and Tchobanoglous, 1998). The nitrate as nitrogen (N) concentration of the employee use is estimated to be 85 mg/L (US EPA, 1980). Two scenarios are presented for consideration: Scenario 1: Current Predicted Employees Per the current Site Approval application, Mr. Jones indicated that the proposed Ford Construction facility will employ six people Monday through Friday, and occasionally Saturday. No customers are anticipated. For six potential employees, the maximum average daily flow for the Site was calculated to be 66.8 gallons per day (gpd): 6 employees x 13 gal/day/employee x 617 days = 66.8 gpd. Scenario 2: Potential Future Employees Because a new Ford Construction office may be built on the Site in the future, and because of the unknown nature of the other businesses which may lease portions of the Site, a value of 100 employees, seven days per week, is also considered in a second nitrate loading analysis. For 100 potential employees, the maximum average daily flow for the Site was calculated to be 1.300 gpd: 100 employees x 13 gal/day/employee = 1,300 gpd. The estimated flow values discussed here should not be used for the design and sizing of the septic system. The design and sizing of the septic system should utilize the San Joaquin County Environmental Health Department On-Site Wastewater Treatment Systems Standards which incorporate peak and surge flow factors. The estimates used in the On-Site Wastewater Treatment Systems Standards may be greater than those discussed here. Nitrate Loading Calculation The following tables presents a summary of the assumptions for, and results of, the nitrate loading calculation for both scenarios on the Site when recharge is derived by the evapotranspiration reduction method with CIMIS data. A modified version of this method is