Boise, ID Accessory Structures: ADU Owner Occupancy (2026)

Idaho's 2023 ADU statute (Idaho Code §67-6511A) is among the most permissive in the western United States. The statute requires every Idaho city to permit at least one ADU per single-family residential lot and prohibits cities from imposing requirements that would make ADU construction impractical — including owner-occupancy mandates that would prevent investor ownership. Boise's modernized Zoning Code Title 11 (effective December 2023) implements this with no owner-occupancy requirement. Property owners may: build an ADU on rental property; rent both the principal dwelling and ADU to separate tenants under independent leases; sell the property with the ADU intact; or use the ADU as a short-term rental (subject to STR registration). This places Idaho alongside California (AB 671), Oregon (HB 2001), and Washington (HB 1337) as states that have preempted local owner-occupancy mandates. Private restrictions remain enforceable: HOA covenants under Idaho Code Title 55 (Real Property) and Title 45 (Liens) may impose owner-occupancy through declarations. Many Boise HOAs in Foothills and master-planned communities (Harris Ranch, Hidden Springs, Surprise Valley) have declaration-based residency rules. Idaho courts generally uphold reasonable covenants when properly recorded and not in violation of state law. Pre-2023 deed restrictions in older neighborhoods may still contain owner-occupancy clauses, subject to interpretation in light of §67-6511A.