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concentration of 0.4 mg/L. Live Oak then averaged the concentrations of the four samples, for a value of 0.30 mg/L-N to represent the nitrate concentration of rain. Because the San Joaquin County Environmental Health Department has requested that local and recent data be utilized wherever possible, the concentration of the Lodi rainwater been selected for use in the nitrate loading calculation. Quantity and Quality of Domestic Wastewater Ms. Delapena proposes to place a four-bedroom home on the Site. A one-bedroom home is currently present. Crites and Tchobanoglous (1998) list a typical flow rate of 50 to 70 gallons per person per day for an individual residence. In the past, San Joaquin County Environmental Health Department has requested that the flow rate be calculated as 140 gallons per bedroom per day to reflect maximum usage. On March 4, 2020, however, Michael Kith, Land Use Program Coordinator at the San Joaquin County Environmental Health Department, stated that he has conferred with Norman Hantzsche (author of the 1992 paper discussed previously), and they have arrived at a new method to determine flow from residential sources. He indicated that wastewater flow from a single-family residence should be calculated as 100 gallons per day (gpd) for the first bedroom and 50 gpd for each additional bedroom; additional residences should be calculated in the same manner (personal communication, March 4, 2020). Using this method, the one-bedroom house would contribute 100 gpd, and the four- bedroom house would contribute 250 gpd, for a total wastewater flow rate of 350 gpd. A typical residential concentration of 35 mg/L of nitrate as N was selected for the residences (Crites and Tchobanoglous, 1998). 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's On-Site Wastewater Treatment Systems Standards (2017) 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. Denitrification Reductions Denitrification is a process that occurs in the septic system drain field whereby certain bacteria oxidize the nitrate (NO3) in the waste water and release nitrogen gas (N2) to the atmosphere. Due to the biologic processes in the shallow soils, nitrogen in the drain field may undergo a reduction between 10 percent to 35 percent. Soils with higher clay content, moist soil conditions, high pH, and organic material denitrify by about 35 LOGE 20-32 Page 7