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 general permits to fifty-eight facilities between 2023-2026. Many of those facilities optimized 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 across permittees to support permit implementation.

Ecology took public comment on the Puget Sound Nutrient General Permit and the Puget Sound Nutrient Reduction Plan. Based on the feedback in 2025 and legal rulings on permit appeals, Ecology decided to not reissue the Puget Sound Nutrient General Permit. Instead, Ecology plans to control nitrogen discharges in the individual permits for the fifty-eight wastewater treatment plants that were formerly covered under the general permit. Ecology will propose individual permit requirements that build on the monitoring, optimization, and planning that was required under the general permit.

Ecology also determined it had more work to do on the Puget Sound Nutrient Reduction Plan, which is its approach to guiding the region in addressing the many human sources of nutrient pollution.

Read the nutrient focus sheet.

Historic information on the general permit, including the comments received in 2025, is available on the Puget Sound Nutrient General Permit web page.

More details on progress in the Resources Library.