ADU Rules in Everett, Washington

Everett (population ~115,000) is the county seat of Snohomish County and the largest city north of Seattle on Puget Sound. Everett is defined by two major employers: the Boeing 777X/787 assembly complex in nearby Paine Field — the world's largest building by volume — and Naval Station Everett, which homeports aircraft carriers and other Navy vessels. The city sits along the Snohomish River delta on Port Gardner Bay and is a regional hub for Snohomish County. Everett is subject to Washington's major statewide ADU reform laws.

Washington State ADU Law: HB 1337 (2023)

Washington HB 1337 (2023) is the foundational statewide ADU law governing Everett. Key requirements:

• Cities must allow up to 2 ADUs per lot — one attached/internal + one detached — by right on any lot with a single-family home
• No owner-occupancy requirement permitted
• No ADU-specific impact fees allowed
• Cities may not require ADUs smaller than 1,000 square feet
• State law limits how restrictive local setback, lot coverage, and height standards for ADUs can be

Washington HB 1110 (2023) accompanies HB 1337, requiring Everett to allow duplexes and middle housing in residential zones.

Everett is subject to the Washington Growth Management Act (GMA), with a comprehensive plan and Urban Growth Area coordinated with Snohomish County.

Everett Local ADU Code

Everett's Planning and Community Development Department administers zoning and building permits. Local ADU regulations must comply with HB 1337 and cannot be more restrictive than state law.

Permitted ADU Types

• Detached ADU: A standalone structure in the rear or side yard
• Attached ADU: An addition to the primary dwelling sharing at least one wall
• Internal/Converted ADU: Conversion of garage, basement, or other existing space

Up to 2 ADUs per lot (one attached/internal + one detached) are permitted.

Size Limits

State law prohibits Everett from requiring ADUs smaller than 1,000 square feet. Confirm current maximum size standards with Everett's Planning Department for your specific zone.

Setbacks

HB 1337 limits Everett's ability to impose setbacks that would effectively prevent ADU construction. Setback requirements vary by zoning district. Verify with Everett's Permit Center before finalizing designs.

No Owner-Occupancy Requirement

State law prohibits owner-occupancy mandates. Everett may not require property owners to live on-site to rent an ADU.

Naval Station Everett — AICUZ Considerations

Naval Station Everett maintains an Air Installation Compatible Use Zone (AICUZ) that addresses noise and accident potential zones associated with military flight operations. While the AICUZ does not prohibit all residential development, properties within high noise zones or accident potential zones may face additional considerations for residential use and ADU construction. Check with the City of Everett Planning Department and consult the Navy AICUZ documentation to determine if your property is affected.

Critical Areas Ordinance (CAO)

Everett's CAO protects the Snohomish River estuary and wetlands, salmon-bearing streams (including the Snohomish River and tributaries), frequently flooded areas (extensive floodplains in the river delta), steep slopes, landslide hazard areas, and seismic hazard zones. Low-lying areas near the waterfront and Snohomish River delta have extensive wetlands and flood-prone land. CAO buffers can substantially restrict ADU siting. Review Everett's GIS maps for CAO constraints before designing.

Seismic Hazard

Everett and the Puget Sound region face significant seismic risk from the Cascadia Subduction Zone (CSZ). Everett's waterfront and delta areas have soft soils and fill susceptible to liquefaction. USGS and Washington DNR seismic maps identify high-risk areas. ADU foundations in susceptible areas require geotechnical assessment. All construction must meet Washington State Building Code seismic requirements.

Permit Process

1. Check your property's zoning, CAO constraints, and flood zone at Everett's online GIS portal
2. Contact Everett's Permit Center for pre-application guidance, especially for waterfront or slope properties
3. Prepare construction plans meeting Washington State Building Code requirements
4. Submit permit application at everettwa.gov or in person at 3002 Wetmore Avenue, Suite 200
5. Plan review and permit issuance
6. Construction inspections
7. Final inspection and Certificate of Occupancy

Contact Everett Permit Center: (425) 257-8731 | everettwa.gov

Disclaimer: This guide provides general information based on Washington HB 1337 (2023) and Everett's municipal code as of April 2026. Zoning regulations change frequently. AICUZ information is for general awareness — consult the City of Everett Planning Department for current military compatibility zone information. Always verify current requirements with City of Everett before making development decisions. This is not legal advice.