Overview
Sewer Authority Mid Coastside WWTF serves Half Moon Bay, California, treating wastewater for 30,500 people. The plant is located near the Pacific coast, within 50 km of the ocean.
The Sewer Authority Mid Coastside WWTF is a municipal wastewater treatment facility serving Half Moon Bay, a coastal city in San Mateo County, California. The plant serves a population of 30,500, placing it in the medium agglomeration category under U.S. regulatory frameworks. 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 or the San Francisco Bay Regional Water Quality Control Board. For a plant of this scale, secondary treatment is typically required, with potential additional nutrient removal if discharging to sensitive waters. The plant's treated effluent is discharged into the local watershed, which ultimately drains to the Pacific Ocean. The coastal environment supports diverse marine life, including kelp forests and migratory species. Protecting water quality is critical for maintaining healthy ecosystems and recreational uses along the San Mateo County coast.
Environmental context
The plant discharges into the Pacific Ocean via local creeks and coastal drainage. The receiving waters support a productive marine ecosystem, including rocky intertidal zones and nearshore habitats for fish, seabirds, and marine mammals. The area is part of the California Current System, a major upwelling zone that sustains rich biodiversity. Protecting water quality is essential for maintaining these ecological functions and supporting local fisheries and tourism.
Frequently asked questions
The plant is located on Frontage Road in Half Moon Bay, San Mateo County, California, United States.
The plant serves approximately 30,500 people in the Half Moon Bay area.
The plant discharges treated effluent into local waterways that flow to the Pacific Ocean, supporting coastal marine ecosystems.
As a U.S. facility, it operates under the Clean Water Act and is regulated by an NPDES permit issued by the California State Water Resources Control Board.
For a medium-sized agglomeration like this, secondary treatment is standard under the Clean Water Act, with possible tertiary treatment if discharging to sensitive coastal waters.
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