WAPATO STP - Wapato, Washington Wastewater Treatment Plant

WAPATO STP is a municipal wastewater treatment plant located on Traders Street in Wapato, Yakima County, Washington. The facility serves a population of roughly 6,375 people, classifying it as a small to medium-sized treatment plant within the state's wastewater infrastructure. As a US-based plant, WAPATO STP operates under the regulatory framework of the Clean Water Act, administered by the Washington State Department of Ecology through the National Pollutant Discharge Elimination System (NPDES) permit program. For plants serving communities of this size, secondary treatment is typically required to meet water quality standards before discharge. The plant's treated effluent is discharged into the Yakima River watershed, which flows into the Columbia River and ultimately reaches the Pacific Ocean. The Yakima River basin supports diverse aquatic life, including salmon runs, and is an important agricultural and ecological resource in central Washington.

WAPATO STP discharges into the Yakima River basin, a tributary of the Columbia River, which drains to the Pacific Ocean. The Yakima River supports critical salmon and steelhead habitats, and the watershed is heavily used for irrigation, making water quality management essential for both ecological health and agricultural productivity.