Ecology proposes nutrient control requirements for three large wastewater treatment facilities

Nutrients like nitrogen are essential to life. But they're too much of a good thing when it comes to the health of Puget Sound. Excessive nitrogen from human sources is entering the Sound and causing algae blooms. When the algae die and decay, they reduce the amount of oxygen in the water, which can harm fish, orcas, and other wildlife.

The Salish Sea Model shows that two-thirds of the excess nutrients in the Puget Sound come from treated human waste discharged from wastewater treatment facilities. The facilities don't produce nitrogen themselves - nitrogen comes from millions of homes and businesses that send wastewater to the facilities. However, the treatment plants form the last line of defense before nitrogen-rich wastewater is released into the Sound.

We invite you to review and comment on draft modifications to the permits for three large wastewater treatment facilities: King County's West Point Wastewater Treatment Plant, the City of Everett's Water Pollution Control Facility, and the City of Bellingham's Post Point Wastewater Treatment Plant.

The modifications, once finalized, will add conditions to the permits to regulate the discharge of nutrients into Puget Sound from these facilities. They're intended to put the facilities on a path towards planning, designing, and constructing new or improved technologies that will significantly reduce the amount of nitrogen they discharge. The proposed modifications also require the communities to optimize the amount of nitrogen they can remove with their existing treatment systems.

By investing in communities, and the critical wastewater infrastructure they rely on, everyone can enjoy a cleaner, healthier future for Puget Sound.

What about the nutrient general permit?

We previously issued a draft general permit to regulate nutrients from 58 wastewater treatment facilities that discharge into Puget Sound. In summer 2025, Ecology accepted public comments on the draft. Based on the feedback we received, as well as legal rulings on permit appeals, Ecology chose not to pursue the general permit approach.

Since Ecology is required to regulate nutrients from wastewater treatment facilities, we are now working to include nutrient control requirements in individual water quality permits, which set the limits for pollutants allowed in treated sewage.

For the 58 Puget Sound facilities that previously had nutrients regulated by the general permit, we are considering several factors as we prioritize updating permits to include nutrient controls. Those factors include the size of the facility, when the facility's permit was last reissued, and whether the permits need to address issues other than nutrients.

What's proposed in these three modifications?

The draft permit modifications propose requirements intended to maximize what the existing treatment facilities can reasonably do to reduce nutrients with their existing technology. They will also begin planning for facility improvements needed to improve nutrient removal in the future. They are focused on four concepts:

• Monitoring the current nitrogen levels in the facilities' discharge water
• Evaluating annual nitrogen loads and requiring corrective actions if they are too high
• Incorporating nutrient reduction into regular operations and maintenance
• Assessing nutrient reduction technologies in two ways:
  • Identifying what treatment changes the community can reasonably afford (called the AKART analysis; AKART stands for all known, available and reasonable methods of prevention, control and treatment). This analysis focuses on identifying the best level of treatment the community can afford to build and operate.
  • What it would take to change the existing treatment systems to achieve a specified low-level nitrogen target (called the Nutrient Reduction Evaluation).

Reducing nutrients won't happen overnight, and we think these changes will help lay a solid foundation for practical solutions that support our growing region and a resilient, thriving Puget Sound.

Public comment periods

We invite you to review and comment on the draft permit modifications. Details about each permit modification and instructions for submitting comments are available on our webpages below:

• Post Point Wastewater Treatment Plant (Bellingham)
• Everett Water Pollution Control Facility
• West Point Wastewater Treatment Plant (King County)

The comment periods run from June 10, 2026 at 12 a.m. to July 10, 2026, at 11:59 p.m.