Don Pedro WWTF - Mariposa County, California Secondary Wastewater Treatment Plant

Don Pedro Wastewater Treatment Facility (WWTF) is located in Mariposa County, California, within the Sierra Nevada foothills. The plant serves a small population of 250 residents and provides secondary treatment, which is the minimum standard for municipal wastewater under the US Clean Water Act. As a small facility, Don Pedro WWTF is designed with a capacity of 151.42 volume units and currently discharges at that same volume. Secondary treatment typically involves biological processes to reduce organic matter and suspended solids. Under the National Pollutant Discharge Elimination System (NPDES), such plants must meet effluent limits to protect water quality. The plant's discharge likely enters a local creek or tributary that flows into the Merced River, which is part of the San Joaquin River basin. This watershed ultimately drains to the Sacramento-San Joaquin Delta and San Francisco Bay. The region supports diverse aquatic life, including salmonid species, making water quality protection important for downstream ecosystems.

Don Pedro WWTF discharges into a local watercourse that feeds into the Merced River, a major tributary of the San Joaquin River. The San Joaquin River flows through California's Central Valley before reaching the Sacramento-San Joaquin Delta and San Francisco Bay. This watershed supports critical habitats for fish and wildlife, including threatened and endangered species. The plant's secondary treatment helps reduce pollutant loads to protect downstream water quality in this ecologically sensitive region.