Washington County, UT Accessory Structures: Tiny Homes (2026)

Zoning code § 10-4-1 splits tiny homes into two categories. " that is "permanently attached or anchored to a foundation or slab," must have "a residential appearance," and "may be permitted as a primary dwelling or accessory dwelling unit" if it meets Appendix AQ of the 2021 IRC. A TINY HOME ON WHEELS (THOW) is the same size range but built on a trailer, and is "only permitted as specifically set forth in the code," meaning it cannot simply be parked as housing. " Under it, a THOW may serve as temporary housing on a lot zoned for single-family dwellings only if: a temporary use permit is obtained before occupancy and renewed yearly for up to three years total; the primary dwelling is owner-occupied with a primary residential exemption on file with the County Assessor; the THOW houses no more than three people and is not used as a short-term rental; utilities meet state and health department standards with a functioning interior bathroom (composting toilets are not permitted); the THOW keeps its wheels road-ready with current registration; generators are barred; only one THOW per lot is allowed; and it must stay out of the building setback, front yard, or street side yard, meeting the setbacks that apply to ADUs. Only immediate family of the property owner, not the broader Title 10 definition of "family," may occupy it.