ADU Rules in Yakima, Washington

Yakima (population ~98,000) is the county seat and largest city of Yakima County in central Washington. Located in the semi-arid Yakima River valley between the Cascades and the Columbia Plateau, Yakima is the agricultural heartland of Washington State — often called the "Apple Capital of the World" for its role as the center of Washington's enormous apple industry. The Yakima River flows through the city, and the surrounding valley produces apples, hops, wine grapes, pears, cherries, and other crops that make Washington one of the nation's top agricultural states. Yakima is subject to Washington's statewide ADU reform laws.

Washington State ADU Law: HB 1337 (2023)

Washington HB 1337 (2023) is the foundational statewide ADU law that applies to Yakima. Key provisions:

• 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 Yakima to allow duplexes and middle housing in residential zones — a notable change for a traditionally lower-density eastern Washington city.

Yakima is subject to the Washington Growth Management Act (GMA) and has a comprehensive plan with an Urban Growth Area coordinated with Yakima County. The GMA is particularly important in the Yakima valley, where agricultural land preservation is balanced against urban growth needs.

Yakima Local ADU Code

Yakima's Community Development Department administers local zoning and building permits. Local ADU regulations must comply with HB 1337.

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 existing garage, basement, or other space

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

Size Limits

State law prohibits Yakima from requiring ADUs smaller than 1,000 square feet. Confirm current maximum size limits for your zone with Yakima's Community Development Department.

Setbacks

HB 1337 limits Yakima's ability to impose setbacks that would prevent reasonable ADU construction. Yakima's residential zones have standard setback requirements that vary by district. Verify current standards with the Permit Center.

No Owner-Occupancy Requirement

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

Critical Areas Ordinance (CAO)

Yakima's CAO protects the Yakima River and its tributaries (including salmon-bearing streams important for Puget Sound salmon recovery via the Columbia River system), wetlands, frequently flooded areas, geologically hazardous areas (including slopes above the valley), and critical aquifer recharge areas. The Yakima River floodplain has FEMA-mapped flood zones. Properties near the river, Naches River, or other streams may have CAO buffer requirements restricting ADU siting. Check Yakima's GIS mapping tools for CAO-regulated features on your property.

Wildfire Risk — Eastern Washington WUI

Yakima's semi-arid climate (averaging around 8 inches of rainfall per year) creates significant wildfire risk. The surrounding hills and foothills are prone to summer wildfires, and properties at the urban-rural interface are in Wildland-Urban Interface (WUI) zones. WUI properties may face additional building code requirements:

• Ignition-resistant construction (fire-resistant roofing, siding, vents, decks)
• Defensible space requirements around structures
• Potential requirements for Class A roof coverings

Check Yakima County's fire hazard maps and consult the Washington State Building Code for WUI construction requirements applicable to your property.

Seismic Hazard

Yakima has lower seismic risk than western Washington but is not immune. The Cascadia Subduction Zone (CSZ) can produce shaking throughout the state, and there are active fault systems in eastern Washington. All ADU construction must meet Washington State Building Code seismic provisions appropriate for the local seismic zone.

Permit Process

1. Check your property's zoning, CAO constraints, and flood zone at Yakima's online GIS portal
2. Contact Yakima's Community Development Department for pre-application guidance
3. Prepare construction plans meeting Washington State Building Code requirements (including any WUI requirements)
4. Submit permit application at yakimawa.gov or in person at 129 N 2nd Street
5. Plan review and permit issuance
6. Construction inspections
7. Final inspection and Certificate of Occupancy

Contact Yakima Community Development: (509) 575-6126 | yakimawa.gov/permits

Disclaimer: This guide provides general information based on Washington HB 1337 (2023) and Yakima's municipal code as of April 2026. Zoning regulations change frequently. Always verify current requirements with Yakima's Community Development Department before making development decisions. This is not legal advice.