SUQUAMISH STP - Wastewater Treatment Plant on Port Madison Indian Reservation, Washington

SUQUAMISH STP is a municipal wastewater treatment plant located on the Port Madison Indian Reservation in Kitsap County, Washington, United States. The facility serves a population of approximately 3,510 people and operates under the regulatory framework of the US Clean Water Act, which requires secondary treatment for discharges to surface waters. The plant provides secondary treatment, a standard biological process that removes organic matter and suspended solids. With a designed capacity of 757.08 m³/day and an average daily flow of 378.54 m³/day, the facility operates at about 50% of its capacity, indicating room for future growth or seasonal variations. The treated effluent is discharged into the Puget Sound, a major estuary in the Pacific Northwest. This water body supports diverse marine life, including salmon, orcas, and shellfish, and is ecologically sensitive to nutrient and pollutant inputs. The plant's coastal location underscores the importance of effective treatment to protect marine water quality.

The plant discharges into the Puget Sound, a large estuarine system connected to the Pacific Ocean via the Strait of Juan de Fuca. This watershed supports critical habitats for salmon, forage fish, and marine mammals. As a coastal facility, SUQUAMISH STP must meet stringent state and federal standards to prevent nutrient enrichment and toxic contamination that could harm the sound's ecological balance.