Paso Robles WWTP - Municipal Wastewater Treatment in Paso Robles, California

Paso Robles WWTP is a municipal wastewater treatment facility located at 3291 Sulphur Springs Road in Paso Robles, San Luis Obispo County, California. It serves a population of about 33,673, placing it in the medium-agglomeration category for U.S. inland communities. As a U.S. facility, the plant operates under the Clean Water Act and is subject to National Pollutant Discharge Elimination System (NPDES) permits issued by the California State Water Resources Control Board. For a plant of this scale, secondary treatment is typically required, with potential additional nutrient controls if discharging to sensitive waters. The designed capacity is 1.00 million gallons per day, indicating a facility sized for the community's needs. The plant's treated effluent is discharged to a receiving water body within the Salinas River watershed, which flows northwest through the Central Coast region to Monterey Bay. The downstream environment supports diverse aquatic life and is important for regional agriculture and coastal ecosystems.

The plant discharges into the Salinas River watershed, which ultimately drains to Monterey Bay in the Pacific Ocean. This coastal watershed supports steelhead trout and other sensitive species, and the river provides critical habitat for migratory birds. The region's Mediterranean climate with seasonal rainfall means stream flows vary significantly, making consistent treatment important for downstream water quality.