Compare ADU zoning rules across 1 Utah cities. Average ADU score: 8.0/10.
Gathered from the 1 city below, with the bill or ordinance each one names. Statewide measures are listed once with the cities they reached, rather than repeated for each.
Statewide law sets a floor; the numbers that decide your project are local. Here is the spread across the 1 Utah city covered here, taken from each city's own ordinance rather than a state summary.
| Question | Across Utah |
|---|---|
| Are ADUs permitted? | 1 of 1 permit them. |
| Detached size cap | Median 1,000 sq ft, from 1,000 to 1,000 sq ft across the 1 cities publishing a numeric cap. |
| Owner-occupancy | Required in 1 of 1. |
| Build cost | $180,000 to $350,000 depending on city and unit type. |
Recomputed whenever a city page changes, so this and the city pages below cannot disagree.
| City | Max Size | Setbacks | Permit Fees | Build Cost | 1BR Rent | Score |
|---|---|---|---|---|---|---|
| Salt Lake City | 1,000 sq ft of gross floor area (21A.40.200.J.1). Only the ADU's floor area counts when the building also holds a garage or other accessory use; stairs to a second-level ADU, loft space under 7 ft and a storage-only basement with no internal connection are excluded (J.3). A covered patio up to 120 sq ft does not count toward the cap but does count toward lot coverage (H.3). Accessory buildings together may cover at most 50% of the rear yard in single/two-family districts (ADU Handbook v2.2). | 3 ft from the rear property line for a detached ADU (21A.40.200.E.3), rising 1 ft per foot of height above 17 ft (F.1.a). Additions, including a second storey on an existing garage, must meet these setbacks; a conversion with no expansion may keep the garage's existing setbacks (E.3 notes). Second-storey windows on a wall within 10 ft of a rear or side line must be clerestory (sill 6 ft up) unless they face the house, an alley, or a commercial or non-residential lot (K). | About $3,000-$5,000 in building-permit plus plan-review fees for a $150,000-$300,000 ADU: permit $1,425.97 plus $8 per $1,000 over $100,000 (Code 18.32.035), plan review 65% of that (FY2027 Consolidated Fee Schedule, amended 6/16/2026). Trade permits and a $35-per-unit rental licence are extra. | $180,000-$350,000 | $1,300-$1,650 | 8/10 |
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