Mason County, WA Fire Regulations: Wildfire Zones (2026)

Mason County Code Section 14.04.010(h) adopts the 2021 Edition of the International Wildland-Urban Interface Code (IWUIC), published by the International Code Council, as amended by Washington Administrative Code Chapter 51-54A, and applies it countywide to unincorporated areas that reach from the Belfair and Allyn UGAs out to the Olympic National Forest boundary and the Skokomish valley. Section 14.08.140, titled IWUIC Section 102.6 Existing Conditions, grandfathers any structure or use that was legally occupied on the date the code was adopted, letting it continue without change except where the IWUIC itself, the International Fire Code, or the Uniform Code for the Abatement of Dangerous Buildings specifically covers it, or where the code official decides a change is necessary for the general safety and welfare of the occupants and the public.

Section 14.08.150, IWUIC Section 106.3, separately exempts certain smaller structures from the IWUIC permit requirement itself, including single-story agricultural buildings of eight hundred sixty-four square feet or less with a wall height up to sixteen feet, and storage buildings of five hundred seventy-six square feet or less with a wall height up to ten feet, each set back ten feet from other structures, though the exemption does not excuse compliance with the IWUIC's fire-protection and construction-material standards or with Chapter 8.52's critical-area rules where a parcel sits in a designated critical area. The county's building official administers permitting and inspection under this chapter, with appeals of any determination routed to the Mason County Hearings Examiner.