ST HELENA WWTF - St. Helena, California Wastewater Treatment Plant

ST HELENA WWTF is a municipal wastewater treatment facility located in St. Helena, Napa County, California. Serving a population of about 5,875, the plant is part of the region's infrastructure supporting the Napa Valley community. As a small to medium-sized facility, it plays a key role in protecting local water quality. The plant operates under the US Clean Water Act, with oversight from the US EPA and California's State Water Resources Control Board. Facilities of this scale typically provide secondary or advanced treatment to meet National Pollutant Discharge Elimination System (NPDES) permit requirements. The designed capacity of 1.00 million gallons per day indicates the plant's ability to handle peak flows. Treated effluent is discharged into a local waterway that drains into the Napa River, which flows southward to the San Pablo Bay and ultimately the Pacific Ocean. The Napa River watershed supports diverse aquatic life and is an important ecological corridor in the region. The plant's operations help maintain water quality in this sensitive watershed.

The plant discharges into a tributary of the Napa River, which flows through the Napa Valley wine region before entering the San Pablo Bay, part of the San Francisco Bay estuary. This watershed supports steelhead trout and other sensitive species, and the plant's treatment processes help reduce nutrient and pollutant loads to protect downstream habitats.