Accessory Structures in Iron County, UT (2026)
5 rules for unincorporated Iron County, Utah.
Verified from official government sources
ADU Rules
In unincorporated Iron County, accessory dwelling units are a permitted use in every residential zone but must follow Iron County Code Section 17.36.400's size, utility, and lot rules. An ADU added onto a home cannot exceed eight hundred square feet, and one built inside the primary dwelling's footprint cannot exceed fifty percent of that home's size. Mobile homes and lots of six thousand square feet or less cannot add an ADU.
Iron County ADU Zoning Standards
Some RestrictionsIron County Code § 17.36.400(B)(1)-(2)
B.General Requirements.1.An accessory dwelling unit (ADU) shall:a.Be connected to the same utility connection for water, sewer, power, gas, etc. as the primary dwelling for which the ADU is secondary. ... c.Provide at least one off-street parking space, in addition to those required by the primary dwelling or guesthouse on the same lot;d.Replace any parking spaces contained within a garage or c...
ADU Owner Occupancy
Unincorporated Iron County requires the legal owner of record to live in one of the two dwellings whenever a property has an accessory dwelling unit. Section 17.36.400(B)(1)(b) makes owner-occupancy a residency requirement, not a suggestion: the owner must sign and record an acknowledgment committing to live in either the primary home or the ADU as a primary residence.
Iron County ADU Owner-Occupancy Rule
Some RestrictionsIron County Code § 17.36.400(B)(1)(b)
b.Meet the residency requirement that the legal owner of record occupy one of the two dwellings of the residential structure in which the ADU is located; and sign and record an acknowledgment stating that the owner of record understands the requirement and will establish one of the two dwelling units associated with the ADU as their primary dwelling;
ADU Rental Restrictions
Iron County bars renting an accessory dwelling unit for less than thirty consecutive days. Section 17.36.400(B)(2)(c) puts ADUs squarely off-limits as short-term rentals in the unincorporated county, even though short-term rentals themselves are separately permitted in residential zones under Section 17.36.200.
Iron County ADU Rental Minimum Stay
Significant RestrictionsIron County Code § 17.36.400(B)(2)(c)
2.An accessory dwelling unit (ADU) shall be prohibited:a.To be created within a mobile home as defined in Section 17.80.010;b.To be created if the lot containing the primary dwelling is six thousand square feet or less in size;c.To be rented or offered for rent for a period of less than thirty consecutive days; andd.To be constructed as a duplex according to the current adopted building code.
Shed & Carport Rules
In unincorporated Iron County, a shed or other accessory building may rise to 35 feet as a multi-story structure under Iron County Code § 17.36.110, but it cannot sit in the required front yard and cannot cover more than 20 percent of the required rear or side yard under § 17.36.020(H). Table footnote (4) sets a 5-foot minimum setback from rear and side property lines.
Iron County Accessory Building and Shed Rules
Some RestrictionsIron County Code §§ 17.16.040 Note (4), 17.36.020(H), 17.36.110
(4)Accessory Building Setbacks and Separations. Unless determined otherwise by the county commission, accessory building setbacks shall be five feet minimum for rear and side yard setbacks. Front yard setbacks are the same as for the principle building and accessory buildings may not be set closer to the front property line than the principle building. Accessory buildings may not be located in ...
Tiny Homes
Iron County Code § 17.16.035 confines tiny homes to the travel trailer park use and caps them at five hundred square feet. A tiny home on wheels tops out at eight feet six inches wide, and a park-model unit built to ANSI A119.5-15 must be at least eight feet wide, with both types restricted to travel trailer parks only.
Iron County tiny home zoning limits
Significant RestrictionsIron County Code § 17.16.035
Tiny Homes: Tiny home on wheels Unknown 8'— 6" max. wide ≤ 500 sq. ft. Travel trailer park Park model (PMRV) ANSI A-119.5-15 8' wide min. ≤ 500 sq. ft. Travel trailer park
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