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Nitrate Loading Study Irerracon Morris Property s Ripon, California September 12, 2018 v Terracon Project No. NA187039 day per resident. Based on a review of the United States Geological Survey (USGS) California Water Science Center California Water Use 2010 Data, average daily domestic use per capita was estimated at 69-gallons per day. The EHD recommends a residential use rate of 70-gallons per person/day times two persons per bedroom. According to information provided by Mr. Morris, the shop building is proposed to be developed with a single restroom including a toilet and sink and will be used as needed. The EPA Water Efficient Single-Family New Hope Specification dated May 2008, indicates toilets and sinks comprise approximately 43.5% of residential average daily effluent. Therefore, a flow rate of 30.5- gallons per day (70-gallons per person per day times 43.5%) was used to calculate potential effluent for the shop building. The rates presented from the references provide general guidance but do not always reflect a match in usage. Should any of the above information provided to our office change or is inconsistent with what is stated, our office shall be contacted to make any necessary modifications to our calculations. Examination and professional judgement, and experience shall be used when selecting a reasonable flowrate. The below table presents the proposed potential septic wastewater use for the site. The flow rates selected for the uses associated with this project are based on EHD recommendations and estimated double occupancy per bedroom. Table 3. Potential Quantity of Effluent. Potential Average Number Number Effluent Average Potential Average Daily Category of of People Quantity per days of Flow use per Bedrooms per Person year (gpd*) Bedroom (gpd*) (4 bedrooms x 2 people per Proposed bedroom x 70 gal. per day x Residence 4 2 70 365 365 days per year)/365 days per year= 560.0 gpd Shop (1 person x 30.5-gal per day Building 1 30.5 365 x 365 days per year) /365 days per year= 30.5 gpd Potential Average Daily Flow 595.5 gallons per day 'gpd -gallons per day Based on a review of Table 3, the estimated potential sewage flow rate for the proposed future residence and shop is 595.5-gallons per day. The average total nitrogen concentration of domestic wastewater is normally considered to be 20 to 85 mg/L-N with 35 to 45 mg/L-N being typical (Crites and Tchobanoglous, 1998). It is estimated Responsive■ Resourceful ■ Reliable 7