Mabton POTW - Secondary Wastewater Treatment Plant in Mabton, Washington

Mabton POTW is a publicly owned treatment works located in Mabton, Washington, a small agricultural community in Yakima County. The plant serves a population of about 2,290 residents and operates under the regulatory framework of the U.S. Clean Water Act, which requires secondary treatment for municipal wastewater discharges. As a facility in a rural setting, it plays a key role in managing local wastewater to protect public health and the environment. The plant provides secondary treatment, a biological process that removes organic matter and suspended solids. It has a designed capacity of 946.35 thousand gallons per day and currently treats an average daily flow of 548.89 thousand gallons, indicating operational headroom. Facilities of this scale in Washington are typically regulated under the National Pollutant Discharge Elimination System (NPDES) by the Washington State Department of Ecology. The treated effluent from Mabton POTW discharges into the Yakima River watershed, which ultimately flows into the Columbia River and then the Pacific Ocean. The Yakima River basin is a critical water resource for irrigation, fisheries, and recreation in central Washington. The plant's secondary treatment helps reduce nutrient and pollutant loads, supporting water quality in this agriculturally intensive region.

Mabton POTW discharges into the Yakima River basin, a tributary of the Columbia River, which flows to the Pacific Ocean. The Yakima River supports diverse aquatic life, including salmon and steelhead, and is heavily used for agricultural irrigation. The plant's secondary treatment helps mitigate nutrient enrichment and pathogen risks in this sensitive watershed, where water quality is vital for both ecological health and human uses.