King County’s Sammamish Plateau Diversion Project looks forward to a busy year

An aerial image of Lake Sammamish, boat docks lining the lake, and it’s evergreen tree-covered shoreline.

February 2024

Welcome to 2024!

We are checking in with a few quick updates about King County's Sammamish Plateau Diversion Project. Moving forward, you can expect to hear from us at least once a month until alternatives are ready for public feedback later this fall.

Before we dive in, a moment for more sewer trivia! If trivia isn’t your thing, use the button to navigate to the project updates below.

Skip Trivia Question


Trivia question - true or false?

In our last email, we covered how this project will build new sewer infrastructure to carry more wastewater from the East Lake Sammamish area to the Brightwater Treatment Plant in Woodinville.

True or false: Which of these statements is true?

  • You can get married at a King County wastewater treatment plant.
  • It's okay to flush all paper products, like paper towels.
  • King County Wastewater Treatment Division grows food.
  • You can expect to detect odor when you are around wastewater facilities.

For answers, keep reading until the “Trivia answer” section.

Trivia Answer


February Project Update

A person in a safety vest and helmet with field equipment, and a pen and paper capturing details about the road.

The Sammamish Plateau Diversion Project will help to serve a growing region. Right now, our project team is hard at work developing project options.

Project teams use all kinds of data to identify workable project options. The team evaluates those options considering a range of factors. Factors include constructability, permitting, community and environmental impacts, and more.

Checking in with your community
Once the project team has identified project options, we will let you know. We will reach out online and in person. You will have opportunities to review options, ask questions, and give us feedback. Currently, we expect outreach to ramp up in fall 2024.

What is happening on the ground
In the coming months, you may notice occasional site visits. Later this year, the project team will perform soil and groundwater surveys. A contractor will sample with drilling equipment. This work can create traffic delays and noise. We will let the community and commuters know what to expect before these surveys begin.

Keep in touch!
We want to make sure that you can access project information and take part in ways that work best for you. Now is a great time to learn about this project! We also want to know about you and your community. We would like to learn how you interact with this area and hear about your values and concerns.

We are committed to meeting you where you are at. Our team can talk or meet one-on-one with you and your neighbors. We can attend a meeting of your group or organization. Please contact us and let us know what works for you to take part!


Trivia Answers

  1. True. You can rent the Brighwater Center for weddings and other special events.
    Weddings and special events - King County, Washington

  2. False. "Unflushables" like wipes, tissues, and paper towels can clog your sewer. Trash in King County's sewer system increases maintenance costs and wears out equipment. Human waste and toilet paper are the only things you should flush. Don’t flush trash - King County, Washington

  3. True. King County Wastewater Treatment Division (WTD) raises about 5000 pounds of fruit and vegetables every year at City Soil Farm in Renton. City Soil's crops go to food banks. WTD also provides biosolids to support managed forests and farms. Home | Loop® Biosolids (loopforyoursoil.com)

  4. False. WTD designs pipes, pump stations, and treatment plants to control odor. Every treatment plant has a 24/7 odor report line. If you detect odor from the County’s system, please let us know as soon as possible so we can investigate the source.
A bride and groom posed with their wedding party at the alter in a ceremony at the Brightwater Hearth Room

Photo credit: A Moments Reflection Photography.


We're here for you!

We know that large construction projects can be stressful for communities. And there are a lot of construction projects going on across the Eastside! We will work with neighbors, businesses, visitors, and commuters every step of the way. We will be here for you all the way through design and construction and into operations. Feel free to contact us at any time!

Contact us

Monica Van der Vieren, Community Services Lead
Monica.VanDerVieren@kingcounty.gov, 206-477-5502
Visit us at kingcounty.gov/SammamishPlateauDiversion


Who we are

For over 50 years, King County Wastewater Treatment Division (WTD) has collected and cleaned wastewater for the Puget Sound region. Over 700 employees work to build and operate King County’s regional wastewater system. WTD serves over 1.9 million people in 17 cities and 17 sewer districts.

WTD is committed to protecting public health and the environment and contribute to a sustainable future for our region.