Can you build a PSL Modular unit in Idaho?

At minimum, an internal one. HB 166 (2025) and Idaho Code 55-3212 establish a statewide right to one internal accessory dwelling unit per homestead and prohibit local governments from banning ADUs outright. Cities can be more permissive — Boise allows up to two ADUs and now recognizes tiny homes on wheels as legal ADUs — but they can no longer simply prohibit them. Confirm your city/county's specifics for detached units, size, and height.

The Division of Occupational and Professional Licenses (DOPL), formerly the Division of Building Safety, through its Modular Buildings program (rules 24.39.31, under Idaho Code Title 39). Every modular unit must obtain an Idaho Insignia, issued after the Division's plant inspection, and a unit can't be occupied without it. Your local jurisdiction then permits the site work — foundation, utilities, zoning.

Snow and seismic. The mountains — McCall, Sun Valley, and the central ranges — carry heavy ground-snow loads that drive roof and structural design, while central Idaho has genuine seismic risk. The Treasure Valley (Boise) is milder. PSL Modular engineers snow and seismic from your site coordinates.

Strongly. McCall, Sun Valley, and similar towns have severe workforce-housing shortages and short build seasons. Modular units are built indoors year-round and set quickly, so projects don't lose a season to winter — and multi-unit orders come off the line in parallel with site prep.

Yes — as of July 1, 2025, Boise updated its zoning to recognize tiny homes on wheels (THOWs) as legal ADUs, and the city allows up to two ADUs per lot. Other Idaho jurisdictions vary, so confirm locally; the statewide floor (one internal ADU, no outright bans) applies everywhere.