Utah ADU Builder
Utah ADU answers · updated 2026-10-17
How many parking spaces can a Utah city require for an ADU?
Utah caps ADU parking: one extra space for an internal ADU, and in specified municipalities at most two for a detached ADU of 650 sq ft or more, or one for a smaller unit. The statutes and the exceptions.
Short answer
For an internal ADU, a city may require one additional on-site space (none if its code already requires four off-street spaces). For a detached ADU in a specified municipality, a city may require at most two spaces for a unit of 650 sq ft or more and one for a smaller unit. Either way, spaces lost when a garage is converted can be required to be replaced.
Internal ADUs (Utah Code 10-21-303)
A municipality may require one additional on-site parking space for an internal ADU, beyond what its code requires for the home, except where its code already requires four off-street spaces. It may also require replacement of garage or carport spaces when the ADU is created inside them.
Detached ADUs (Utah Code 10-21-304)
A specified municipality's detached-ADU rules may not require more than two on-site spaces assigned to a detached ADU of 650 sq ft or larger, or more than one for a unit under 650 sq ft. When a detached garage is converted, the city may require the home's required spaces that were in it to be replaced on site.
Some city codes adopted before October 1, 2026 still list higher numbers. Where a city page shows one, ask the city how it applies the state cap: the statute limits what a specified municipality's detached-ADU rules may require.
Sources
City rules come from this site’s dated research; each city page lists its official sources. This is planning information, not legal advice. How the property screen works.