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Coal Creek sewer upgrade
The Coal Creek Sewer Upgrade Project will install new sewer pipes to carry more wastewater and meet the growing needs of Bellevue and Newcastle.
We have received reports of people getting unsolicited phone calls from the Coal Creek Project Hotline 206-492-6499. These calls were not made by King County staff. We are currently investigating these reports.
If you receive a call from this number, please do not answer or call it back. Please block the number. We are investigating this technical issue. We apologize for the inconvenience.
Project description
The Coal Creek Sewer Upgrade Project will upgrade a regional sewer line that serves Bellevue and Newcastle. Built between 1966 and 1991, the existing pipeline is nearing its maximum capacity and needs to be upgraded to carry more wastewater and meet the growing needs of the community.
Once installed, the new sewer pipe will serve the area for another 50 years or more.
Project update
August 2025
Take our survey to help us keep you informed during construction! Pre-construction survey closing soon!
King County knows that construction can impact community members. The Coal Creek Project team wants to hear from you and your community about how best to keep you informed during construction.
Our pre-construction survey is open through September 12. Taking the survey requires approximately three to five minutes. Participants can reply to questions in their preferred language. We are not collecting any personal identifying data, and all data entries are optional.
Take the Pre-Construction Survey
Connect with us at upcoming events!
The Coal Creek Project outreach team will be at two upcoming community events. Stop by our booth to learn more about the project and what to expect as construction approaches. We hope to see you there!
Newcastle Days
- When: Saturday, September 6, 10am-7pm
- Where: Lake Boren Park, 13058 SE 84th Way, Newcastle, WA 98056
Salmon Days Festival
- When: Saturday & Sunday, October 4 & 5, & 10am-6pm
- Where: Downtown Issaquah, WA
Interested in a project briefing for your community group?
We are available meet with you or come to your next community event. The project team share the latest project information and talk about what will happen over the next several years of construction. Please contact Frances Kuo 206-492-6499 or CoalCreekProject@kingcounty.gov.
Sign up for the project email list to get updates, learn about construction, and find outreach activities that you can participate in!
Previous project updates
- Pre-construction survey closing soon!, August 2025
- Coal Creek project awarded Salmon-Safe Certification, April 2025
- News release: King County’s major sewer upgrade in Bellevue is the first project of its kind to earn Salmon-Safe certification, simultaneously modernizing infrastructure and improving habitat, April 9, 2025
- King County's Coal Creek Sewer Upgrade Project is heading into construction in 2025!, April 2025
- Survey work in the Coal Creek Sewer Upgrade Project area beginning this month, March 11, 2025
- Heads up: Work in Coal Creek Natural Area beginning mid-July, July 9, 2024
- Crews will install equipment to monitor conditions in the Coal Creek Natural Area as early as April 24, April 26, 2024
- Protecting and restoring the Coal Creek project area, Winter 2023
- Protecting and restoring the Coal Creek project area, February 16, 2023
- Did you see the latest project updates? June 3, 2022
- Winter 2022 newsletter, March 2022
- Opportunities for input- one ends, another begins, January 6, 2022
- Bringing in the New Year with a project update, January 3, 2022
- Neighbor feedback needed on parking/transportation options on Forest Drive Southeast, August 16, 2021
- Tree surveys starting, and more time to add your input! August 9, 2021
- Reaching out to the community: Accessibility ideas for the Red Cedar Trailhead, July 27, 2021
- Crews will carry out surveys in the Coal Creek Natural Area beginning June 18, June 16, 2021
- Crews will carry out surveys in the Coal Creek Natural Area beginning April 14, April 8, 2021
- Upcoming geotechnical surveying near 130th Ave SE, March 1, 2021
- Field work continuing for the Coal Creek Sewer Upgrade Project, February 5, 2021
- Self-Guided Tour Signs, October 2020
- Project newsletter, September 2020
- Field work complete by Friday, August 28, trail impacts reduced on Thursday and Friday, August 26, 2020
- Field work making progress; expected to wrap up Friday, August 28, August 2020
- Field work underway in August- weekday trail closures beginning Monday August 3rd, July 2020
- Sewer upgrades in the works: Join us June 17 & 23 to learn more! June 2020
- Work coming up in Coal Creek Natural Area, May 2020
- Utility location with lane closure on Coal Creek Parkway starting as early as May 15, May 2020
- Final design is underway for the Coal Creek Sewer Upgrade Project! April 2020
- Roadwork with lane closures on Coal Creek Parkway starting as early as April 27, April 23, 2020
- Planned Coal Creek Natural Area surveying at the end of March and in early April, March 23, 2020
- Data gathering at pre-existing survey locations will start as early as February 26, February 19, 2020
- Minor maintenance activity in Coal Creek Parkway tomorrow, December 18, December 17, 2019
- Fall 2018 newsletter
- Field survey update: Work begins on Coal Creek Parkway Monday, July 15, July 12, 2019
- Field investigations coming up in Summer 2019, June 7, 2019
- Tree surveying for the Coal Creek Sewer Upgrade Project beginning May 7, May 2019
- Survey work in the Coal Creek Natural Area beginning March 11, February 2019
- A King County sewer upgrade project is coming to your area, December 2018.
(View online version.) - Tree surveying in Coal Creek Natural Area Wednesday-Thursday, September 5-6, August 2018
- Field work for a new sewer line in Coal Creek Area continues in July, July 2018
- Survey activity week of May 14, 2018, May 2018
- Geotechnical work in the Coal Creek Parkway area begins in January, updated January 9, 2018
- Geotechnical work in the Coal Creek Parkway area begins in January, December 2017