Idaho Building Codes

Idaho has NO mandatory statewide residential building code. Code adoption is entirely LOCAL - cities and counties decide whether to adopt codes and which editions. Major cities (Boise, Meridian, Idaho Falls, Coeur d'Alene) typically use IRC 2018/2021 with local amendments. MOST counties do NOT enforce codes in unincorporated areas (Ada County is notable exception). Approximately 60% of Idaho land area has NO building code. Statewide trades codes: Electrical, plumbing, HVAC permits required statewide through DBS. Climate Zones: 5B (Treasure Valley), 6B (most of state), 7 (mountain areas). Snow loads: 20-400+ psf (EXTREME variation - verify site-specific). Ice barrier required throughout (all zones). Frost depth 24-48". Extensive WUI/wildfire risk. Seismic SDC D in Teton Valley/eastern Idaho. No statewide GC/roofing license (contractor registration required). 44 counties.