Facility Site ID: 2694
Cleanup Site ID: 4292

  • Site Status

  • Cleanup Started
  • Process Type

  • Independent

Site Background

A picture of the landfill in its current closed state.
A picture of the landfill in its current closed state.
The Cathcart landfill is a closed, 60-acre municipal solid waste landfill regulated under Chapter 304 Washington Administrative Code.

The Site was constructed in 1980 and closed in 1992.  It was the first landfill in Washington constructed with a bottom liner in accordance with new federal standards.  The landfill is bounded by private residential property to the northwest, north and east, and by other Snohomish County facilities to the south and west.

Long Term Monitoring

Cathcart Way Operations Center Site Map
Cathcart Way Operations Center Site Map
Post-closure care is required until the landfill generates little to no leachate and landfill gas, landfill settlement has stabilized, and groundwater quality criteria have been satisfied.

Currently groundwater is sampled semiannually for most wells; additionally, landfill gas is sampled quarterly, and surface water is sampled semiannually.

Annual monitoring reports are located in the electronic documents on the left side of this
webpage.

Who Manages Post-Closure Care For The Landfill?

 Snohomish County Public Works manages post-closure care for the landfill.

Who Is The Regulatory Authority For The Landfill?

Snohomish County Health Department is the jurisdictional health department that permits the landfill. For more information, please email EHQuestions@snohd.org or call (425) 426-4607 and reference Cathcart Landfill.

What Is Ecology's Role In The Regulation Of Landfills?

Ecology's Solid Waste Management Program maintains regulatory standards and provides technical assistance to the jurisdictional health department. 

When Is A Permitted Landfill Subject To The Model Toxics Control Act?

Permitted landfills are potentially subject to the state’s cleanup law, the Model Toxics Control Act (MTCA) if there has been a release of hazardous substances from the landfill.

Learn How Ecology Is Protecting The Environment In Your Community

What's In My Neighborhood shows contamination cleanup sites in Washington state. Ecology works to clean up these sites to protect the health of people, plant, and animals. Cleanups are construction projects that remove, treat, or contain potentially harmful substances.

Report An Environmental Issue

Northwest Region Office
Northwest Region Office

To report an environmental problem or concern, any time, day or night, use the online reporting form

Counties: Island, King, Kitsap, San Juan, Skagit, Snohomish, and Whatcom

Email
nwroerts@ecy.wa.gov
Phone: 206-594-0000

Requesting Accommodation

Ecology is committed to providing people with disabilities access to information and services. To request an ADA accommodation, contact Ecology by phone at 360-407-6831 or email at ecyadacoordinator@ecy.wa.gov. For Washington Relay Service or TTY call 711 or 877-833-6341.  Visit Ecology’s website for more information.

​If you speak a non-English language, free language services are available.

Technical Reports 14
Document Title Document Date Document Type
Cathcart Landfill - 2025 Annual Monitoring Report 4/28/2026 Monitoring Report
Cathcart Landfill - SHARP Report 9/30/2025 Site Hazard Assessment and Ranking Process Report
Cathcart Landfill - 2024 Annual Monitoring Report 3/4/2025 Monitoring Report
Cathcart Landfill - 2023 Annual Monitoring Report 2/8/2024 Monitoring Report
Cathcart Landfill - 2022 Annual Monitoring Report 3/22/2023 Monitoring Report
Cathcart Landfill - 2021 Annual Monitoring Report 3/10/2022 Monitoring Report
Cathcart Landfill - 2020 Annual Monitoring Report 2/10/2021 Monitoring Report
Cathcart Landfill - 2019 Annual Monitoring Report 3/1/2020 Monitoring Report
Cathcart Landfill - 2018 Annual Monitoring Report 3/1/2019 Monitoring Report
Cathcart Landfill - Phase II Hydrogeologic Study and Mitigation Measures Evaluation 5/31/1995 Site Specific Technical Document - Other
Cathcart Landfill - Comprehensive Hydrogeologic and Engineering Study, Phase 1 2/2/1994 Site Specific Technical Document - Other
Cathcart Landfill - Installation of Groundwater Extraction Well and Monitoring Well for Mitigation of Leachate-Impacted Groundwater Flow into the North Stormwater Detention Pond 11/26/1991 Site Specific Technical Document - Other
Cathcart Landfill - Geophysical Investigation for Mitigation of Leachate Impacted Groundwater Flow into the North Stormwater Detention Pond 9/1/1991 Site Specific Technical Document - Other
Cathcart Landfill - Special Report 3/6/1981 Site Specific Technical Document - Other
There may be more documents related to this site. To obtain documents not available electronically, you will need to make a public records request.

Places to see print documents

  • Solid Waste Program - Northwest Regional Office
    15700 Dayton Ave N
    Shoreline, 98133
    This location may only have print documents available during open comment periods.

Contaminants 3

Contaminant Type
Soil
Groundwater
Surface Water
Air
Sediment
Bedrock
Metals - Metals - Other S C
Metals - Arsenic S C
Halogenated Organics - Other Halogenated Organics S C
S
Suspected
C
Confirmed Above Cleanup Levels
B
Below Cleanup Levels
RA
Remediated-Above
RB
Remediated-Below
R
Remediated
This contaminant list was based on our best information at the time it was entered. It may not reflect current conditions at the site.