Island County, WA Building Safety: Building Permits (2026)

010 adopts the International Building Code, International Residential Code and related state codes by reference as the Island County Building Code, and ordinarily any construction covered by those codes needs a permit reviewed and issued by the Island County Building Department. 040 spells out the one broad exemption the county writes into its own text: a Group-U occupancy structure, the International Building Code's category for low-hazard storage and agricultural buildings, needs no permit, fee or inspection at all when it's accessory to a private residence or used for agricultural purposes.

That exemption has a dollar and size ceiling. Once the value of materials for the exempted structure passes $1,000, the owner must instead obtain an alternative building permit, and the county limits that alternative permit to structures no larger than 1,000 square feet, so a bigger or more expensive accessory building falls back under the full International Building Code permit process. The Building Official designs the application form for the alternative permit, which must list who will build the structure, who owns the land, the structure's location, the materials' value and the type of structure, and the applicant pays a fee set by Board resolution.

030, a standard building permit, once issued, is good for 24 months, can be renewed once for another 12 months at half the original fee, and after that a new permit and a new valuation are required to finish the work.