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system(s) at the property may use septic tanks, leachfields, and seepage pits in number and dimension appropriate for the anticipated waste loading based on the number of people at the property, the duration of their presence, and San Joaquin County regulations. 6.0 SEPTIC SYSTEM EVALUATION This section presents an evaluation of the current septic system a suitability study of the property for an expansion of the septic system to accommodate loadings associated with use of Church facilities. San Joaquin County sewage standards were supplied to Dames & Moore after the liquid loading estimates were completed, and therefore were not used in this section. The liquid and nitrogen loadings of the current septic system are evaluated in Section 6.1 , and the liquid and nitrogen loadings of the septic system needs associated with the Phase 1 and Phase 2 expansions of the Church are discussed in Sections 6.2 and 6.3. 6.1 CURRENT SEPTIC SYSTEM The current septic system was installed in 1976. The system was permitted by the San Joaquin Local Health District. A copy of the permit is attached in Appendix A. The system consists of a 1 ,600 gallon concrete tank, a distribution box, and three leach lines installed in 19 inches of gravel fill. Each leach line extends 40 feet from the distribution box and ends in a seepage pit drilled to a depth of approximately 25 feet bgs. 6.1 .1 Liquid Loading Based on the infiltration test results, the infiltration rate for each leach line is likely to be limited to 0.25 inches per hour. This infiltration rate suggests that the 120 total feet of leach lines may allow less than 20 gallons/hour to infiltrate into soil at the property (see Appendix F for calculations). Standard estimates prepared by the United States Environmental Protection Agency (EPA) suggest that residential water use would average approximately 45 gallons/ person-day (EPA, 1980). This suggests that four to six residents would produce approximately 11 .3 to 16.9 gallons per hour assuming the 45 gallons per person was produced during a 16 hour period (for calculations, see Appendix F). Given that peak water use may exceed 17 gallons for this four bedroom residence, the septic system - requires infiltration capacity in addition to that provided by the leach lines. SAC 125.12 7 DAMES & MOORE