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I. INTRODUCTION Chesney Consulting has been retained by Mr. Ramon Rios to complete the requirements of the San Joaquin County Environmental Health Department(EHD) for the proposed construction of a small "boutique"winery and tasting room with an associated septic system, located at 8482 West Linne Road in Tracy, California. The Environmental Health Department has been at the forefront of nitrate impact investigations and the prevention or mitigation of environmental contamination from various sources of nitrate, particularly septic systems. EHD requires these investigations and corresponding septic system operational criteria under Community Development Title 9-1105.2 (d) for projects in unsewered areas, in areas currently impacted with nitrate, or for projects that may potentially impact the underlying groundwater with nitrate. The EHD's main concerns regarding this project are 1.) The current environmental condition of the soil and groundwater under the proposed wastewater disposal area, 2.)Natural nitrate impact mitigation measures through septic system operation to alleviate future nitrate impact to the underlying groundwater, 3.)Assurance that sufficient wastewater disposal area exists to accommodate the average daily flow from the proposed septic system, 4.) Assurance that there is sufficient 100%replacement area that will remain designated as such, in the event of system failure, or a need to "rest"the primary disposal area, and 5.)Assurance that the primary disposal field and 100%replacement area comply with the 100 foot rule, as stated in the S.J.C. Sewage Standards Section 8.1, Page 15, in which a sewage disposal area must be 100 feet from a non-publicly operated domestic well. In addition, the EHD has specified that the existing septic system that serves Mr. Rios' house, which is located to the west of the proposed winery,be removed due to unsatisfactory conditions`, and a new 1,200 gallon septic tank be installed to serve the house. Effluent from this tank will gravity flow east to a new 2,000 gallon septic tank that will serve the winery. Combined effluent will then be equally pressure distributed throughout a new filter bed. A. SUMMARY OF FINDINGS The findings of our study reveal there are highly favorable soil characteristics in the upper surface soil strata where the combined septic effluent will be distributed. These characteristics include a high clay content soil that may: 1.) Create anaerobic microsites to prevent nitrification, 2.) Nitrification that does occur may be denitrified during soil saturation, and 3.) Promotion of evapotranspiration because of the microscopic soil porosity. A pressurized filter bed system utilizing Infiltrator Chambers® is proposed to be installed to take advantage of these favorable surface soil characteristics. The on-site domestic well that serves Mr. Rios' house and will serve the winery and tasting room has an upper-middle nitrate concentration at 30 ppm. This area of Tracy has comparatively high nitrate concentrations in domestic wells typically over the Maximum Contaminant Level of 45 ppm. Chesney Consulting