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Recommendation: 39

Status: Complete

Develop a National Pollutant Discharge Elimination System permit framework for advanced wastewater treatment in Puget Sound to reduce nutrients in wastewater discharges to Puget Sound by 2022.


Action 1

Develop a Puget Sound Nutrient General Permit to control wastewater discharge from sewage treatment plants.

Implementation Details

Wastewater treatment plants discharge more than 50 percent of the human sources of nutrients into Puget Sound and contribute significantly to low levels of dissolved oxygen. The Washington Department of Ecology proposes developing a Puget Sound Nutrients General Permit to control nutrient discharges from domestic wastewater treatment plans (sewage treatment plants) through its National Pollutant Discharge Elimination System regulatory authority. The alternative to a general permit is to include nutrient control requirements in each treatment plant’s individual permits as they are reissued during the next 10 years.

Recent Progress

The Department of Ecology was given $535,000 to develop a Puget Sound Nutrient General Permit for wastewater treatment plants to reduce nutrient pollution input into the water. The department issued the first permit December 1, 2021, and it is effective January 1, 2022 to December 31, 2026. The permit applies to fifty-eight domestic wastewater treatment plants discharging to marine and estuarine waters of the Salish Sea in Washington. Information and fact sheets about the permit can be found online.

The Department of Ecology recently posted about how wastewater treatment plants slow the flow into Puget Sound. It also made a video on solving Puget Sound nitrogen pollution.

More details may be found in the progress reports in the resources library.