Caldwell, ID Accessory Structures: Tiny Homes (2026)

Caldwell has no ordinance using the phrase 'tiny home,' so a tiny dwelling is classified by how it is built and placed. A tiny house set on a permanent foundation and built to code is treated like any site-built dwelling or, if it is a second unit, as an accessory dwelling unit under City Code 10-12-03-1, which requires a 200-square-foot minimum, limits the unit to one bedroom, and applies accessory-structure setbacks and the Chapter 10 height schedule. A tiny house on wheels is generally classified as a recreational vehicle, and 10-12-03-1 expressly prohibits using a recreational vehicle as an ADU; mobile homes are also prohibited, and manufactured or modular units are only allowed on a permanent, code-compliant foundation. Manufactured homes installed within Caldwell must meet the manufacturer's installation requirements, or, where those are unavailable due to the structure's age, the State of Idaho's installation standards, under City Code 12-01-25. At the state level, Idaho rules generally prohibit living in a recreational vehicle on a standard residential lot, allowing RV residential use only in licensed RV parks. The practical result is that to live in a tiny home in Caldwell year-round, it must be permanently foundation-set and permitted, not parked on wheels.