Eastsound WD STP - Secondary Wastewater Treatment on Orcas Island, Washington

Eastsound WD STP is a municipal wastewater treatment plant located on Orcas Island in Eastsound, Washington, serving a population of approximately 1,500 residents. The plant is situated near the Orcas Island Airport and operates as part of the island's critical water infrastructure. The plant provides secondary treatment, the standard level required by the U.S. Clean Water Act for municipal wastewater. With a designed capacity of 908.50 thousand gallons per day and an average discharge volume of 264.98 thousand gallons per day, the facility operates well below its capacity, indicating room for future growth or seasonal variability. Treated effluent is discharged into the marine waters of the San Juan Islands, a sensitive ecological area in the Salish Sea. The region supports diverse marine life, including salmon, orcas, and seabirds, making proper wastewater treatment essential for protecting water quality and ecosystem health.

The plant discharges into the marine environment of the San Juan Islands, part of the Salish Sea watershed. This area is ecologically sensitive, supporting critical habitats for salmon, forage fish, and marine mammals. The discharge must comply with Washington State water quality standards to prevent nutrient enrichment and protect shellfish beds and recreational waters.