WARDEN DOMESTIC STP - Grant County, Washington Wastewater Treatment Plant

WARDEN DOMESTIC STP is a municipal wastewater treatment facility located in Grant County, Washington, serving a population of approximately 2,690. The plant provides secondary treatment, a standard level for communities of this size under the U.S. Clean Water Act. The plant has a designed capacity of 1,173.47 megaliters and currently treats an annual discharge volume of 681.37 megaliters. As a facility in the Pacific Northwest, it operates under the National Pollutant Discharge Elimination System (NPDES) permitting program, which sets effluent limits to protect water quality. The treated effluent is discharged into the local watershed, which ultimately drains into the Columbia River basin. The Columbia River supports diverse aquatic life, including salmon runs, and is a critical resource for irrigation, recreation, and hydropower in the region.

The plant discharges into the Columbia River basin, a major Pacific Northwest watershed that flows into the Pacific Ocean. The river supports ecologically significant habitats, including spawning grounds for salmon and steelhead, and provides water for agriculture and communities downstream. Protecting water quality in this basin is essential for maintaining regional biodiversity and ecosystem health.