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RECEIVED <br /> �prt'�e� �pQouccc��� <br /> FEB 17 2W <br /> tNVIR09b1ENTAL HEALTH <br /> February 16, 2017 PERWTISERVICES <br /> FOR: Mr. Rodney Estrada,REHS <br /> San Joaquin County Environmental Health Department(EHD) <br /> 1868 Hazelton Ave. <br /> Stockton, CA 95205 <br /> Mr. and Mrs. Jonathan Williams <br /> 21647 Eastern Heights Road <br /> Linden, CA 95236 <br /> PROJECT: Second Unit Dwelling(Mother-in-Law Unit)Project <br /> 21663 Eastern Heights Road, Linden, CA 95236 <br /> SUBJECT: Soil Suitability/Nitrate Loading Studies Report Addendum. Project Number 03.17A <br /> Reference is made to my Nitrate Loading Study dated January 31,2017, Project Number NLS-03.17 for <br /> the project listed above. This Addendum has been requested by EHD because it is now a requirement of <br /> EHD to specify 2 people per bedroom for projected flow volumes from a residential unit. The flow <br /> volume value assigned by EHD is 70 gallons/person/day, or 140 gpd for each bedroom. The EHD also <br /> accepts a flow volume of 150 gallons/day/bedroom. <br /> Domestic flow volume projections have been approximated in the USEPA Onsite Wastewater Treatment <br /> Systems Manual on Page 3-4. Residential(domestic)flow volumes average approximately 69 <br /> gallons/person/day, which was used in my Report for this project. On Page 3-2,the Manual states"The <br /> current code practice is to assume that maximum occupancy is 2 persons per bedroom,which provides an <br /> estimate that might be too conservative if additional factors of safety are incorporated into the design." <br /> Although these two factors of gallons/person/day and persons/bedroom concern flow volumes,they also <br /> affect the nitrate loading calculations. In my Nitrate Loading Study Report, I assigned one person per <br /> bedroom at 69 gallons/person/day for a total of 276 gpd,but I incorporated a significant safety factor by <br /> stating this flow volume is generated every single day of the year. <br /> The Hantzsche/Finnmore Formula is used below to recalculate the nitrate loading using the 2 <br /> persons/bedroom factor requirement. The calculations demonstrate nitrate loading remains slightly under <br /> the MCL. <br /> Calculated nitrate-nitroeen loading from the entire subiect property: <br /> IN(1 -d)+RNh <br /> Nr= (I+R) <br /> Where: <br /> Page I of 2 <br /> P O. BoX3794 OTurlock CA 95381 (i)office(209)668-1403 aFax(209)668-2598 <br />