Winston Green STP - Douglas County, Oregon Wastewater Treatment Plant

Winston Green STP is a municipal wastewater treatment plant located in Douglas County, Oregon, United States. It serves a population of about 11,290 residents in the surrounding community. The plant is situated inland, more than 50 km from the Pacific coast. As a facility serving a medium-sized agglomeration, the plant is expected to meet secondary treatment standards under the U.S. Clean Water Act, administered by the Oregon Department of Environmental Quality (DEQ) through the National Pollutant Discharge Elimination System (NPDES) permit program. The regulatory framework ensures that the plant provides adequate treatment to protect water quality. The treated effluent is discharged into local waterways that ultimately drain to the Pacific Ocean via the Umpqua River basin. The plant plays a key role in maintaining the health of the watershed, which supports diverse aquatic life and provides habitat for salmon and other species.

The plant discharges into the Umpqua River basin, which flows westward through the Coast Range and empties into the Pacific Ocean near Winchester Bay. The watershed supports critical salmon and steelhead runs, and the plant's operations help protect these fisheries from nutrient pollution and pathogens. The region's forested landscape and seasonal rainfall influence runoff patterns and treatment demands.