This bill modifies existing state building code and related statutes to require the state building code council to adopt the International Wildland Urban Interface Code (IWUIC) by rule after completion of statewide wildfire hazard and base-level county risk maps, with a specified deadline of November 1, 2029 for adoption once those maps are complete. It reenacts and amends RCW 19.27.031 and amends RCW 19.27.560 and RCW 43.30.580 to add or clarify requirements for model code adoption cycles, interim and emergency amendments, solicitation of first responder input, collaboration with the Department of Natural Resources, regional fire defense boards, local governments, building officials, and urban forestry specialists, and coordination of defensible space provisions with environmental and planning agencies. Jurisdictions issuing permits for parcels mapped as high or very high hazard must apply the IWUIC as described, counties and cities may prepare or use local maps until statewide maps are complete, and after statewide maps are finished local maps must use substantially similar criteria. The bill also directs a state department to establish a technical assistance program and to develop and administer a grant program (subject to available funding and appropriations) to help counties, cities, and towns develop findings of fact and maps identifying wildland urban interface areas. It requires establishment and public posting of a statewide wildfire hazard map (designating low, moderate, high, very high) and a base-level county risk map (identifying vulnerable resources), a method for local governments to update maps with local assessments approved by the jurisdiction's fire marshal, and public disclosure of the criteria and analysis used. Amendments to an interface code that affect single-family or multifamily residential buildings are not effective unless approved by the building code council under RCW 19.27.074(1)(b). No new criminal penalties or substantive criminal-law changes are included in the extracted text; the changes are procedural and substantive code-adoption and mapping requirements. The text provided is incomplete in places: the identity of "the department" referenced in some provisions is not specified in these excerpts, a provision about local amendment authority to the IWUIC ends mid-sentence, and the full criteria and content of the statewide wildfire hazard and base-level risk maps are defined in RCW 43.30.580, the full text of which is not included here.

If enacted, the state will publish statewide wildfire hazard and county risk maps and the Department of Natural Resources will coordinate review with regional fire defense boards; those maps will be posted online and, once complete, the State Building Code Council must adopt the International Wildland Urban Interface Code by November 1, 2029 so its building rules apply in areas the maps mark as high or very high hazard. Counties, cities, and towns must create or update local maps (with their fire marshal’s sign-off) and either use the statewide criteria within six months of the statewide maps being finished or have their locally adopted maps match those criteria; local jurisdictions can get technical help and apply for grant money to develop maps and findings, but funding is subject to legislative appropriations. The parties most affected are local governments, property owners, and builders in areas designated high or very high hazard: local governments will need staff time and possibly outside help to prepare or revise maps and adopt code changes, and developers and homeowners in those zones will likely face new building permit requirements or construction/retrofit obligations that can raise costs. State agencies and the Building Code Council will take on coordination, rulemaking, and approval duties, but the text leaves unclear which “department” runs the grant and assistance programs and how much funding will be available, so actual financial support and some implementation details remain uncertain.