Idaho’s New Zoning Laws Require Cities to Allow Manufactured Homes and ADUs

Idaho cities must now allow manufactured single-unit homes wherever they permit single-family housing. The state’s new zoning law, signed by Gov. Brad Little, removes restrictions that previously limited where such homes could be placed. The law also requires cities to allow accessory dwelling units (ADUs) by right in many zoning areas and prevents local governments from banning them outright.

Cities may no longer impose hard maximum size caps on ADUs, though they can still enforce health, safety, and infrastructure standards. The law also bars local rules that require minimum lot sizes above 1,400 square feet or impose specific setbacks, depths, or fees. These changes are designed to increase housing supply in response to rising home prices in Idaho’s major cities, including Boise, Coeur d’Alene, Idaho Falls, and Twin Falls, which saw some of the largest home price increases between 2019 and 2023.