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.

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 department of Ecology proposes developing a Puget Sound Nutrients General Permit to control nutrient discharges from domestic wastewater treatment plants and 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.

The Department of Ecology awarded the general permit to fifty-eight facilities in about three years. Many of those facilities were able to adjust their operations to reduce the amount of nitrogen entering Puget Sound, helping them avoid major financial investments.

Ecology also started the Puget Sound Nutrient Reduction Grant Program, awarding $9 million to support permit implementation. Ecology received $10 million from the Legislature to continue this grant program and expects to accept applications in summer 2025.

In response to a Pollution Control Hearings Board ruling, Ecology proposed in June 2025 to make the general permit voluntary. Ecology plans to issue the updated permit in fall 2025 so that facilities can determine which approach–general permit or individual permit–they will use to reduce the amount of nitrogen entering Puget Sound. Information about the permit is online.

More details on progress in the Resources Library.