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Comprehensive Solid Waste Management Plan
Learn more about our Comprehensive Solid Waste Management Plan, which sets strategies for managing solid waste over the next 6 to 20 years in King County. It guides the many public and private elements that make up the regional solid waste system.
Updating the Comp Plan
Washington State law (RCW 70.95.080) requires each county to prepare a coordinated plan for handling regional waste.
Development schedule
Updated May 2025 (subject to change)
| Date | Actions/Events/Public meetings |
|---|---|
| April 24, 2024 | Long-Term Disposal City Subgroup Meeting |
| May 20, 2024 | Long-Term Disposal City Subgroup Meeting |
| June 17, 2024 | Long-Term Disposal City Subgroup Meeting |
| Aug 26, 2024 | Long-Term Disposal City Subgroup Meeting |
| Sept 30, 2024 | Long-Term Disposal Open House |
| Oct 9, 2024 | Long-Term Disposal Open House |
| March 12, 2025 | City Comp Plan Subgroup Meeting |
| April 2025 | Long Term Disposal Study Complete |
| April 16, 2025 | City Comp Plan Subgroup Meeting |
| May 14, 2025 | City Comp Plan Subgroup Meeting |
| June 18, 2025 | City Comp Plan Subgroup Meeting |
| July 16, 2025 | City Comp Plan Subgroup Meeting |
| Aug, 13, 2025 | City Comp Plan Subgroup Meeting |
| 2025-2026 | State Environmental Policy Act and Environmental Impact Statement Process |
| Q1 2028 | 60 Day Public Review Begins |
| Q1 2028 | 120 Day Department of Ecology Review Begins |
| Q3-Q4 2028 | Executive Office Approval, Transmit to Council for Review |
| Q1 2029 | Council Approval |
| Q2 2029 | 120 Day City Approval Begins |
| Q3 2029 | 120 Day Ecology Approval Begins |
| Q4 2029 | Comp Plan Adopted |
Adopted Comprehensive Plan (2019)
Washington State law (RCW 70.95.080) requires each county to prepare a coordinated plan for handling regional waste. King County’s current Comprehensive Solid Waste Management Plan was adopted in November 2019. It outlines goals and strategies for the next 6 years, with consideration for the next 20 years. We also review the plan every 3 to 5 years for necessary updates.
2019 Comprehensive Solid Waste Management Plan
As part of the State Environmental Policy Act (SEPA), we prepared an Environmental Impact Statement (EIS) with the 2019 Comprehensive Plan. The EIS looked at potential environmental impacts of the facilities, programs, and services outlined in the plan. It also includes measures to avoid or reduce adverse impacts.
Final Environmental Impact Statement (EIS)Notice of Issuance and Availability
Long-Term Disposal Study
The Cedar Hills Regional Landfill is projected to reach full capacity by 2040. As detailed in the 2019 Comp Plan, the Solid Waste Division must propose the County's next long-term disposal method in the next version of the Comp Plan. The Long-Term Disposal Study analyzes five disposal options to determine the best option(s) for the region.
- Long-Term Disposal Study
- Appendix A – Environmental Impact Factors and Assumptions
- Appendix B1 – Comparative Evaluation Summary Matrix: Low Tonnage
- Appendix B2 - Comparative Evaluation Summary Matrix: Medium Tonnage
- Appendix B3 - Comparative Evaluation Summary Matrix: High Tonnage
- FAQ
The Frequently Asked Questions document addresses common questions to the study results and is not meant to be a summary of the study.
Long-Term Disposal Advisory Committee Subgroup
Members of the Metropolitan Solid Waste Advisory Committee (MSWAC) formed a Long-Term Disposal Subgroup to fully explore long-term disposal options and provide insights. The Subgroup’s recommendations are shared with both Solid Waste advisory committees to help inform decision-making around Long-Term Disposal, Comp Plan updates, and ILA extensions.
Meeting 1
An overview of past studies on long-term disposal and a review of how the 2019 Comp Plan laid out this work to move forward.
Meeting 2
A deep dive with our consultants into 3 options: Gasification, Pyrolysis, and Refuse-derived Fuel.
Meeting 3
A deep dive with our consultants into 2 options: Waste Export by Rail and Mass Burn.
Meeting 4
A more detailed discussion on Waste Export by Rail and Mass Burn.
The above meetings provided insight into the issues around the long-term disposal options most important to the advisory committee members. With this information, the Division held two open house sessions to present the background and results of the long-term disposal work to a larger group of advisory committee members and city representatives.
Feasibility studies
Municipal Solid Waste-To-Fuels Study
2023 study exploring the feasibility of producing sustainable aviation fuel from municipal solid waste.
Full report – Municipal Solid Waste To Liquid Fuels Study
Rate restructure study
2021 report evaluating alternative revenue options to reduce reliance on garbage fees.
Solid Waste Cost of Service and Rate Restructure Study
Waste-to-Energy and Waste Export
2019 study evaluating the feasibility of using either Waste-to-Energy or Waste Export by Rail as the County’s next disposal method.
Waste-to-Energy & Waste Export by Rail Transportation Study
Task 2 Waste-to-Energy Existing Conditions Memorandum
Appendix A - Waste-to-Energy Existing Conditions Memorandum
Task 3 Waste-to-Energy Options and Solid Waste Export Considerations
Nov. 6, 2017, PowerPoint presentation: Waste-to-Energy Options and Solid Waste Export Considerations - Normandeau Associates
"Waste to Energy" and "Solid Waste Export Considerations" presentations
2007 comparison of waste export with other emerging technologies as alternative options to landfilling
Disposal Options Comparative Evaluation
Anaerobic Digestion
2017 study exploring the feasibility of an anaerobic digestion program to support resource recovery and climate action goals.
Anaerobic Digestion Feasibility Study
Sustainable Solid Waste Management
2014 study looking at approaches for creating a more sustainable regional system.
Sustainable Solid Waste Management Study
Optimized Transfer Station Recycling
2013 study to identify the best national options for recycling and waste diversion.
Previous plans
2007 Transfer and Waste Management Plan
In collaboration with our partner cities, we created the 2007 Transfer and Waste Management Plan. It was adopted by King County Council in 2007. We also prepared an Environmental Impact Statement (EIS) to supplement the 2001 Comp Plan final EIS.