Caldwell, ID Accessory Structures: Garage Conversions (2026)

Caldwell's City Code does not contain a stand-alone provision titled 'garage conversions.' A conversion is instead handled through the Building Safety Division building-permit process and the zoning code. The key question is what the converted space becomes. If a homeowner converts a garage into additional living area that remains part of the single main dwelling, it is treated as a building alteration requiring permits for any structural, electrical, plumbing, or egress and fire-rating changes. If the conversion creates a separate, independently habitable unit with its own kitchen and bath, it becomes an accessory dwelling unit and must comply with City Code 10-12-03-1, which sets a 200-square-foot minimum, a one-bedroom limit, accessory-structure setbacks (or the zoning-district setbacks when attached to the principal residence), and the Chapter 10 height, setback, and area schedule. Converting a required parking space can also trigger Caldwell's off-street parking standards, so the home may need to replace any parking the garage previously provided. Manufactured or modular elements may not be used to create a dwelling unless on a permanent, code-compliant foundation. Because the city handles conversions case by case, owners should confirm permit and parking requirements with Community Development before starting work.