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Our unwavering commitment to protecting Puget Sound includes the shallow bays where excess nitrogen from human sources, under the right conditions, can be a risk to marine life.

We support a science-based approach that capitalizes on the latest technology and focuses public resources where they make a real difference.

A proposal by the Department of Ecology would impose a blanket permit on regional utilities throughout Puget Sound. In King County, that would require us to build a fourth regional wastewater treatment plant, a multi-billion project that would take more than a decade of planning and construction, and will displace people and businesses somewhere in Seattle in an area about twice the size of Seattle Center.

Ecology’s proposal would limit our ability to take actions now that would produce better results sooner for salmon and orcas.

King County Marine Biologist surveying Puget Sound

There is so much at stake with this permit, both for the health of Puget Sound and for the health of communities. We have a responsibility to make sure an investment of this magnitude will achieve the most environmental uplift possible.​

We have asked Ecology to course-correct its current approach to allow for a truly collaborative dialogue focused on these issues and sustainable solutions to them.

There are targeted, evidence-based actions we can quickly take here -- and that Ecology could require us to take that are not currently regulatory requirements -- that would reduce nutrient inputs into Puget Sound and offer substantial ecological benefits beyond nitrogen reduction.

Effective ways to reduce nitrogen in Puget Sound

The path Ecology has chosen does not provide a level of certainty regarding environmental benefits that justifies the certain enormous cost. But if we course-correct now, we can achieve faster, more equitable strategies that are based on a solid scientific foundation and produce multiple benefits that matter. We want to participate in a constructive conversation with stakeholders about what collective actions we can take to achieve shared goals.

An aerial view of Puget Sound

King County wants what’s best for Puget Sound. We want faster, more equitable strategies that are based on a solid scientific foundation and produce multiple benefits that matter. We want to participate in a constructive conversation with stakeholders about what collective actions we can take to achieve shared goals.

We have to make sure that the next steps we take are the most thoughtful and strategic ones we can identify with the information we have in hand – the health of Puget Sound and extraordinary public and ratepayer investments are on the line as we make these choices. We believe there is a wiser, more sustainable approach, and we would like to work together to set us on a better path.

Nitrogen reduction FAQs

Dissolved oxygen (DO) is a measure of how much oxygen is dissolved in the water. It represents the amount of oxygen available to aquatic plants and wildlife. Concentrations of DO in Puget Sound vary seasonally and from year to year. Hypoxia is a condition that deprives a water body of adequate oxygen and can occur when the amount of DO becomes too low to support most aquatic life.

Low DO is most concerning in shallow bays with poor circulation and where seawater does not flush in and out as strongly. This can occur particularly in the late summer and early fall. Sixteen bays throughout Puget Sound are modeled to have persistent levels of low DO. While these levels are largely due to natural factors, it is important that all human-caused influences be studied as well.

Nitrogen and phosphorus are the primary nutrients needed to support plant growth in aquatic ecosystems. In the right levels and setting, they are beneficial. But too many nutrients can lead to excessive plant growth. In Puget Sound, increased nitrogen can result in increased phytoplankton growth. When that happens, DO is consumed as the phytoplankton eventually decompose. Other impacts that could be linked to excess nitrogen include algae blooms, kelp and eelgrass loss, and increases in jelly fish. It’s important to note these effects are also influenced by variables like temperature and light.

Most (88%) of nitrogen in Puget Sound comes from the ocean. The second biggest source is wastewater treatment plants, at 7%. Watershed runoff delivers another 5%. Less than half of that runoff amount come from human sources like agriculture, septic systems, and urban development, the rest is from the atmosphere and plants. It is important that programs and regulations for nitrogen carefully study and address the levels and locations of all human-caused sources.

Reducing nitrogen inputs from wastewater treatment plants will not be enough to meet the desired dissolved oxygen levels sought by the Washington State Department of Ecology. Additional steps will be needed in the areas most impacted. Solutions could include habitat restoration, reducing agricultural pollution and run-off, promoting kelp farming, or providing more tax breaks and grants for homeowners to improve their septic systems.

Water quality investments, like green stormwater solutions and cleanup of contaminated sediments and sites, will have a greater impact on improving the quality of life in communities that experience a greater pollution burden. Stormwater investments will result in more measurable results than removing nitrogen from wastewater. If King County has to raise rates dramatically for funding to treat wastewater, there may be less to spend on steps that provide measurable improvements for aquatic life, including salmon and orca.

There is evidence that changes in ocean conditions and climate may have much larger effects on Puget Sound dissolved oxygen and the Sound’s ecosystem than nitrogen inputs from wastewater. Nitrogen and dissolved oxygen concentrations in incoming ocean water are changing in ways that may overpower any changes in nitrogen due to local human impacts.

Other cities and counties in Washington that treat for nutrients discharge into rivers and shallow bays that are very sensitive and where nitrogen can have an immediate, localized impact. King County discharges deep into central Puget Sound where water currents and circulation are much stronger. King County is also a very dense urban area. Since the Growth Management Act was adopted, only 3% of growth in King County has been outside the urban growth boundary. This is good for the environment because it prevents urban sprawl. But a dense urban area means there is little space for adding wastewater treatment infrastructure.

To reduce nitrogen to the levels required in the Draft Permit, each treatment plant would need to be modified. At the biggest plant, West Point, the design change would significantly reduce how much wastewater could be treated. There is no room to expand on the current footprint of West Point. To retrofit the existing secondary treatment facilities to add the advanced treatment, those facilities would have to go offline for several years. To avoid wastewater being released into Puget Sound with only primary treatment, a fourth treatment plant would need to be designed, constructed and in operation in coordination with the work at West Point.

No. A new, fourth treatment plant would only take a portion of the flow currently treated at West Point. We will need the capacity from West Point well into the future.

If a fourth regional treatment plant is needed, the preferred general location would be north of downtown Seattle and reasonably close to West Point. Ideally, a new location should minimize the need for costly new large, underground pipes. If a site near the existing pipelines could not be found then new underground pipelines and pump stations would also have to be built. The fourth treatment plant would require a site approximately 130-150 acres in size. For comparison, that is about twice the size of Seattle Center, and it will not be easy to find large, suitable parcels. We estimate the cost would be very high and require a significant sewer rate increase, thus making King County an even less affordable place to live.

No. The three existing regional wastewater treatment plants - South Plant, Brightwater, and West Point - were planned for and built to handle volumes for our area through the year 2060. You can read more about their design and levels of capacity in the 2019 Treatment Plant Flows and Loadings Study.

Get involved

The Washington State Department of Ecology on Dec. 1, 2021 issued its Puget Sound Nutrient General Permit . You are welcome to share your suggestions and ideas with key decision-makers and program staff:

  • State Department of Ecology: Eleanor Ott, Nutrient General Permit Lead | Email
  • King County Council | Contact your Councilmember
  • King County Department of Natural Resources and Parks | Rebecca Singer, Resource Recovery Section Manager | Email
  • Regional Water Quality Committee | Home page