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" \ SAN J0A0UIN p <br /> c� Environmental Health Department <br /> COUNTY Jasjit Kang, REHS, Director <br /> Greatness grows here. Muniappa Naidu, REHS,Assistant Director <br /> PROGRAM COORDINATORS <br /> Jeff Carruesco, REHS, RDI <br /> Willy Ng, REHS <br /> Steven Shih, REHS <br /> Elena Manzo, REHS <br /> Natalia Subbotnikova, REHS <br /> May 27, 2026 <br /> JOE MURPHY <br /> DILLON AND MURPHY ENGINEERING <br /> P.O. BOX 2180, <br /> LODI, CA 95241 <br /> RE: Soil Suitability and Nitrate Loading Study <br /> 10779 S. Airport Way, Manteca CA 95336 <br /> SU-2601339, APN: 177-500-28 <br /> The San Joaquin County Environmental Health Department (EHD) has reviewed the Soil Suitability and <br /> Nitrate Loading (SSNL) Study dated May 2026, and submitted May 13, 2026, and has the following <br /> comments for your consideration. <br /> The SSNL was prepared to determine the suitability for onsite wastewater treatment system (OWTS) <br /> usage and the potential long-term impact of nitrate to groundwater from the Minor Subdivision under PA- <br /> 25000278. The current parcel size is 12 acres. The proposed Parcel 1 is to be 9.99 acres and proposed <br /> Parcel 2 is to be 2.01 acres. <br /> Based on the information provided, the EHD can make the following findings: <br /> 1. The SSNL reports a nitrate-loading estimate for the proposed Parcel 1 with the existing four (4) <br /> bedroom home and assumed 2-bedroom ADU OWTS of 5.23 milligrams per Liter (mg/L) of NO3- <br /> N (Nitrate as Nitrogen), the proposed Parcel 2 with the existing 2-bedroom residence and no <br /> additions OWTS of 10.0 mg/L of NO3-N (Nitrate as Nitrogen); the maximum contamination level <br /> for NO3-N in groundwater is 10.0 (mg/L) set by the Central Valley Regional Water Quality Control <br /> Board. The septic system construction shall follow the San Joaquin County OWTS where <br /> applicable. (SJC OWTS Standard 7.1). <br /> EHD concurred with the calculation for the proposed Parcel 1 nitrate loading estimate as stated <br /> in the report, but EHD calculated a higher value for the proposed Parcel 2 nitrate loading estimate. <br /> Report stated Parcel 2 would be 9.98 mg/L and EHD calculated 10 mg/L of NO3-N. <br /> 2. Based on the information provided the EHD finds that the SSNL Study supports the suitability for <br /> standard OWTS usage for the proposed development pursuant to San Joaquin County <br /> Development Title, Section 9-604.010(d). <br /> 3. The Percolation test conducted on May 1, 2026, yielded a percolation rate of 35.71 minutes per <br /> inch (MPI) for proposed Parcel 1 and 16.66 MPI for proposed Parcel 2. At this rate, a minimum of <br /> 5 feet of soil separation is required between the bottom of the dispersal field and the groundwater <br /> as mitigated by the proposed standard septic system for proposed Parcel 1 and 8 feet for <br /> proposed Parcel 2. The SSNL reports groundwater level at about 25 feet below surface grade. <br /> (San Joaquin County OWTS Standard Table 1.10.2). <br /> 1868 E. Hazelton Avenue I Stockton, California 952051 T 209 468-3420 1 F 209 468-3877 1 www.sjgov.org/ehd <br />