Nutrient pollution is a serious problem in Puget Sound, and communities across the region are working to address this problem by updating wastewater treatment plants. Now, the Washington Department of Ecology is proposing changes to the general permit that regulates nutrients, specifically nitrogen, for 58 wastewater treatment plants discharging into Puget Sound.
Ecology proposes to change the Puget Sound Nutrient General Permit to give wastewater treatment plants the choice of having their nitrogen discharges regulated under the general permit or their individual wastewater discharge permits.
The proposed updates to the Puget Sound Nutrient General Permit come in response to a February 2025 ruling from the state’s Pollution Control Hearings Board ruling. The decision is a result of appeals to the original general permit, issued by Ecology in 2021. The Pollution Control Hearings Board determined that Ecology does not currently have the authority to make the general permit mandatory, given that wastewater treatment plants already have individual water quality permits from Ecology that authorize wastewater discharges.
“The Board’s ruling means that we are adjusting our method while staying on the path to a healthier Puget Sound – facilities can either opt in to the general permit or they can receive nitrogen control requirements in their individual permits. We continue to see the general permit as the most efficient and effective way to address the nutrient pollution coming into Puget Sound. It provides the path for more flexibility, more coordinated funding, and the potential for nutrient trading in the future.”
-David Giglio, manager of Ecology’s water quality program
Nitrogen from wastewater treatment plants is one of the main sources of nutrient pollution for Puget Sound, which is why Ecology established a regional solution with the general permit. Wastewater plants do not produce nitrogen themselves – it comes from millions of homes and businesses – they form the last line of defense before nitrogen-rich wastewater is released into the Sound.
Nitrogen control requirements are common in many parts of the state and the country but, until Ecology developed the general permit, were not required for most wastewater treatment plants in Puget Sound. All wastewater treatment plants in Washington have individual water quality permits that regulate the type and amount of pollutants the facilities can discharge.
Starting in 2019, Ecology held a public process to determine the best permitting approach to reduce the amount of nitrogen discharged to the Sound from 58 wastewater treatment plants. The agency established the general permit in 2021, charting a path for those plants to optimize their current operations while investing in and installing nitrogen control technologies in the next 15-20 years. This meant these facilities were under the general permit for their nitrogen discharges and had their individual permit for all other water quality requirements. The general permit offers more flexibility for addressing nutrient pollution than facility-specific individual permits, such as allowing communities with multiple wastewater facilities to plan their investments where it is most cost effective.
Other proposed changes
In addition to allowing eligible facilities to opt in to the general permit, Ecology is proposing to establish new due dates for facility reports that take into account the reissuance process that is underway. In response to a 2025 U.S. Supreme Court ruling, Ecology is also proposing language that clarifies facilities covered under the general permit are only responsible for the quality of their discharge and not for the quality of the receiving waters that their treated wastewater goes into.
Ecology plans to finalize the changes to the general permit later this summer, with the opportunity for facilities to opt in beginning this fall. For facilities that choose to address nutrient pollution through their individual water quality permits rather than the general permit, the agency will use a number of factors in prioritizing the timing of individual permit updates.
In the state budget the Legislature passed in May, Ecology received $10 million to continue the Puget Sound Nutrient Control Grant program, which supports investments in nutrient pollution control technologies.
“Controlling nutrient pollution from municipal wastewater treatment plants is critical to our success in restoring Puget Sound and recovering salmon populations. These are significant investments, and we appreciate the ongoing support from the Legislature to provide funding to support these communities as they work to protect Puget Sound.”
- David Giglio
Provide input
Ecology is accepting public comments on this permit reissuance from 9:00 a.m. June 18 to midnight, July 25, 2025. Materials are available for review on our Puget Sound Nutrient General Permit webpage.
Submit comments online, by mail, or at a public hearing:
- Comment online
- Mail to:
William Weaver, Ph.D., P.E.
Department of Ecology
Water Quality Program
P.O. Box 47696
Olympia, WA 98504-7696
Upcoming workshops and hearing
Ecology will hold a virtual information session and a virtual public hearing during the comment period. The information session will include a presentation followed by questions and answers. No formal comments accepted.
- July 1, 2025
Register on Zoom
The public hearing will include a presentation with time for questions and answers, followed by an opportunity for formal public comment.
- July 22, 2025
Register on Zoom