Cedar Hills Regional Landfill Development
Learn about the development and facilities relocation plans and read the Final Environmental Impact Statement (EIS) for Cedar Hills Regional Landfill.
Since 1965, the Cedar Hills Regional Landfill has provided for the safe and efficient disposal of the county's solid waste. It is the only remaining open landfill in King County.
The landfill receives over 800,000 tons of solid waste a year from about 1.4 million people in King County, except for residents in Seattle and Milton.
In 2019, the King County Council and its partnering cities approved the 2019 Comprehensive Solid Waste Management Plan. The plan sets strategies for managing solid waste in King County over the next 6 to 20 years. It addresses all aspects of the regional solid waste system, including:
- Curbside collection
- Processing of recyclable and compostable materials
- Transfer and disposal of garbage
The plan also authorizes the Division to consider alternatives to maximize the capacity of the Cedar Hills Regional Landfill to meet the county's disposal needs.
To meet the region's need for waste disposal services, King County's Solid Waste Division is working on a project to ensure there is adequate capacity in the Cedar Hills Regional Landfill to continue accepting garbage beyond 2028.
The landfill site development plan project involves several components.
We began by evaluating a No Action Alternative and 3 Action Alternatives for developing a new area (Area 9) for garbage disposal. This new area will be located in the southeast part of the landfill property.
In November 2022, after careful consideration of environmental and technical analysis, as well as non-environmental factors such as cost, policy considerations, and operational benefits, the Solid Waste Division identified its preferred alternative, Action Alternative 2, for landfill development.
The project calls for a plan for relocating landfill support facilities, to the landfill buffer or next to the Renton Transfer Station, to make room for development of the new disposal area. These facilities include:
- Vehicle maintenance shop
- Office space and parking for employees
- Tractors, trailers, and operations vehicles
- Laboratory space
The support facilities that would be relocated to Renton or the landfill buffer will not handle garbage or other waste. No landfilling would occur at the location next to the Renton Transfer Station.
We were required to create a plan for pursuing a Special Use Permit to place the new facilities within the existing northern or southern buffer zone.
As the property owner, King County, not the Solid Waste Division, may authorize other uses within the buffer. A Special Use Permit will be needed to allow non-landfilling uses, such as relocating landfill support facilities, within the buffer.
Environmental review process
The State Environmental Policy Act (SEPA) requires that state and local agencies consider the probable adverse environmental impacts of a project before taking action. The King County Solid Waste Division, as lead agency on the project, is responsible for conducting the environmental review.
SEPA process summary
There are three milestones in the EIS development process:
- Scoping: gives the public the opportunity to review and comment on what will be studied in the Draft Environmental Impact Statement (EIS).
- Draft EIS: allows the public to review and comment on the plans or actions an agency is proposing, including the mitigation measures to reduce, minimize, or avoid harmful environmental impacts.
- Final EIS: comments on a Draft EIS are considered in the development of a Final EIS, which informs the agency's decision on which plan or action will be selected to move forward.
For more information about the State Environmental Policy Act (SEPA) process, visit the Washington State Department of Ecology
The Solid Waste Division has determined that one or more of the alternatives being considered has the potential to result in a significant adverse impact to the environment. On July 25, 2019 the Solid Waste Division issued a Determination of Significance.Read the Determination of Significance
A 30-day scoping period from July 25 to August 26, 2019 gave the public, tribal governments, and local, state, and federal agencies an opportunity to comment on the range of alternatives, areas of impact, and possible mitigation measures the EIS should evaluate. Comments received were considered by the project team developing the Draft EIS.
On August 12, 2019, the Solid Waste Division hosted a scoping meeting at the King County Library System Service Center, 960 Newport Way NW, Issaquah. Members of the public were invited to drop in to learn more about the proposal, ask questions, and provide written and oral comments.
The Draft Environmental Impact Statement (EIS), issued September 16, 2020, evaluated and described the potential impacts on the environment of the project alternatives.
The Final EIS includes modifications to the text stemming from the comments received on the Draft EIS. As part of SEPA requirements, the Final EIS contains a Responsiveness Summary (Appendix M), which provides the public with responses from the Solid Waste Division to all the questions and comments that were received during the public comment period for the Draft EIS. The text of the Final EIS was revised as needed to clarify or correct information.
Updated March 2022 (subject to change)
July 25, 2019
King County Solid Waste Division issued a Determination of Significance and Request for Comments on the Scope of the Environmental Impact Statement.
Aug 12, 2019
A Scoping meeting was held at the King County Library System Service Center, 960 Newport Way NW, Issaquah. Members of the public were invited to drop in to learn more about the proposal, ask questions, and provide written and oral comments.
July 25 –
Scoping period, a 30-day period that gave the public, tribal governments, and local, state, and federal agencies an opportunity to comment on the range of alternatives, areas of impact, and possible mitigation measures the EIS should evaluate. Comments received were considered by the project team developing the Draft EIS.
Sept 2019 – Fall 2020
Draft EIS is prepared.
Sept 16, 2020
The King County Solid Waste Division issues a Draft EIS for public review.
Nov 6, 2020
Deadline for comments on the Draft EIS.
March 22, 2022
Final EIS is issued and includes responses to comments received on the Draft EIS.
|Nov 2022||Action Alternative 2 is identified as the preferred alternative.|
June 2020 – May 2025
Design and permitting for selected landfill site development alternative.
June 2025 – Mid 2028
Potential construction of new landfill area, Area 9, within the Cedar Hills Regional Landfill property.
Final Environmental Impact Statement (EIS)
2020 Site Development Plan Final EIS
Notice of Availability, Final EIS
Final EIS - Appendix J, Part 1
Final EIS - Appendix J, Part 2
Final EIS - Appendix J, Part 3
2010 site development plan
The 2010 Cedar Hills Site Development Plan was unanimously approved by the King County Council in December 2010.
View the Cedar Hills Regional Landfill 2010 Site Development Plan
The final Environmental Impact Statement (EIS) for the 2010 Site Development Plan was issued in July 2010.
Final EIS cover letter, fact sheet, table of contents, abbreviations, glossary and summary
Final EIS, Chapter 1: Introduction and Background
Final EIS, Chapter 2: Alternatives
Final EIS, Chapter 4: Air and Odor
Final EIS, Chapter 5: Surface Water
Final EIS, Chapter 6: Groundwater
Final EIS, Chapter 7: Upland Vegetation, Wetlands, and Wildlife
Final EIS, Chapter 8: Noise and Vibration
Final EIS, Chapter 9: Human Health
Final EIS, Chapter 10: Land Use
Final EIS, Chapter 11: Scenic Resources – Aesthetics, Light, and Glare
Final EIS, Chapter 12: Cultural Resources
Final EIS, Chapter 13: Transportation
Final EIS, Chapter 14: Public Services and Utilities
Final EIS, Chapter 15: Greenhouse Gases
Final EIS, Chapter 16: References
Final EIS, Responsiveness Summary
Final EIS, Appendix A: Special Permit and Related Documents
Final EIS, Appendix B: Municipal Solid Waste Handling Permit
Final EIS, Appendix C: Distribution List for Final EIS
Final EIS, Appendix D: Threatened and Endangered Species Documentation
Final EIS, Appendix E: Supplemental Technical Memoranda