Washington Statewide Rule

Washington State Wildland Urban Interface Code

Heavy RestrictionsApplies statewide across Washington (2026)

Washington adopted the International Wildland-Urban Interface Code statewide under RCW 19.27. New construction in designated WUI areas must meet ignition-resistant building, defensible space, and water supply requirements.

Key Facts

Statute: RCW 19.27.560
Code Adopted: International WUI Code
Effective Date: July 2024
Mapping Authority: Department of Natural Resources

Source: Washington State Legislature

Full Breakdown

Under RCW 19.27.560 and the State Building Code Council rules (WAC 51-55), Washington adopted the International Wildland-Urban Interface Code (IWUIC). Effective July 2024, new construction and substantial alterations in mapped wildland-urban interface areas must comply with ignition-resistant exterior materials, ember-resistant vents, defensible space requirements, and adequate water supply for fire suppression. The Department of Natural Resources publishes WUI maps under RCW 76.04. Local jurisdictions enforce the code but cannot weaken state minimum requirements.

Violations & Penalties

Building code violations may result in stop work orders, civil penalties, denial of certificates of occupancy, and removal of non-compliant construction.

Frequently Asked Questions

How do I know if my property is in a WUI zone?

The Washington Department of Natural Resources publishes wildland-urban interface maps under RCW 76.04. Contact your local building department or DNR to verify your property's status.

Do existing homes need to retrofit?

The IWUIC primarily applies to new construction and substantial alterations. Existing structures generally are not required to retrofit unless undergoing major renovations triggering code compliance.

Sources

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Full Breakdown

Frequently Asked Questions

How do I know if my property is in a WUI zone?

The Washington Department of Natural Resources publishes wildland-urban interface maps under RCW 76.04. Contact your local building department or DNR to verify your property's status.

Do existing homes need to retrofit?

The IWUIC primarily applies to new construction and substantial alterations. Existing structures generally are not required to retrofit unless undergoing major renovations triggering code compliance.