Canyon County, ID Accessory Structures: ADU Owner Occupancy (2026)

Canyon County's zoning ordinance treats a second dwelling on a residential or agricultural lot in unincorporated Canyon County, Idaho as a Secondary Residence under § 07-14-25, and imposes two firm conditions. First, the owner of the lot or parcel containing the secondary residence must live on the property, an owner-occupancy requirement that prevents an absentee owner from renting out both the primary home and the secondary unit to unrelated tenants. Second, the secondary residence must carry its own address, with address numbers posted on the home so fire and emergency crews can find it separately from the primary dwelling.

The secondary residence use is one of the listed uses governed by Article 14, Use Standards, which applies wherever the county's land use matrix allows the use as a permitted use, conditional use, or director's decision under § 07-10-27. A certificate of zoning compliance from the Development Services Department is required before the secondary residence can be occupied, per § 07-12-01. Because this is a zoning standard, not a building code provision, it sits alongside but separately from any structural or utility requirements a secondary residence must also meet.

The rule applies only to unincorporated Canyon County; Caldwell, Nampa, Middleton and the county's other incorporated cities set their own accessory dwelling or second-unit standards, which can differ substantially from the county's owner-occupancy condition.