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Project update

February 2021

Wondering what the new facility will look like? Here is our current rendering :

Rendering of the Loop Vehicle Maintenance Facility

King County anticipates that construction on the new Loop Vehicle Maintenance Facility will begin in 2021. A new completion date will be updated as soon as we know more.

What is the Loop Vehicle Maintenance Facility Project?

King County Wastewater Treatment Division (WTD) is designing a new vehicle maintenance and staging facility for transporting Loop biosolids. The new facility will be located in North Bend (exit 34 off I-90) on County-owned land.

Why is King County building this facility?

  • The current vehicle facility is located in south Seattle, on a space leased from the King County Airport. The lease on this land is now ending without the option to renew, requiring WTD to relocate the facility.
  • Helps meet new federal regulations that limit the time a driver can be on the road.
  • This facility reduces driving time and improves safety for every traveler on our highways and roads.

Learn more: view about this project and frequently asked questions.

What are Loop biosolids?

Loop biosolids are a nutrient-rich soil amendment created from King County wastewater. As it has for 40 years, the County produces Loop from solids extracted during the wastewater treatment process. Loop is used on farms and forests by commercial growers in both Eastern and Western Washington.

Learn more about Loop biosolids at:


Contact us

Contact Eunice Lee at:

Project schedule

Construction is expected to begin in 2021.

Fall 2016 – Winter 2016
Winter 2016 – Winter 2018
  • Study site conditions (plants, animals, soils, cultural resources, topography, etc.) to determine if there are specific site constraints
  • Begin preliminary facility design
  • Acquire necessary permits and complete required environmental review
  • Work with neighbors and the community to understand needs and constraints during construction and facility operation
  • Gather public input on some project elements. Specific topics for community feedback included choice of plants for landscaping and color of building
  • Design the facility structures
  • Hire a construction contractor
  • Build the new facility
  • Work with neighbors and the community to provide progress updates and notice of construction
  • Staff a 24/7 hotline during construction

Working with the community

King County will work with the public, community groups, and other key stakeholders to provide project information, identify potential impacts, and involve the community during construction where possible.

Community members can expect:

  • Advanced notice of meetings and construction
  • Community group and neighbor briefings
  • Project newsletters and fliers
  • Project web page updates, including frequently asked questions
  • Construction hotline

Project location

Back to the capital projects overview map .

project site mapThis project is located in North Bend, WA. The site is between 468th Avenue SE, SE 144th Street, and SE 146th Street, off I-90 east, exit 34. View larger version of map .