Utah ADU questions, answered with sources

Can you build an ADU on a quarter-acre lot in Utah?

Usually yes for an internal ADU, and it depends on the city for a detached one. A quarter acre is 10,890 sq ft, which is above the 6,000 sq ft size at or below which Utah lets cities ban internal ADUs, but 110 sq ft under the 11,000 sq ft floor where S.B. 284 requires specified cities to permit a detached ADU.

Does Utah require the owner to live on the property to have an ADU?

State law doesn't impose owner occupancy itself, but it lets cities require it, and most do. For an internal ADU, a city may bar renting the unit when the home isn't the owner's primary residence. For a detached ADU, S.B. 284 lets a city require the owner to live in the main home or the ADU. 63 of the 102 cities on file require it in some form.

Can an HOA stop you from building an ADU in Utah?

Generally not for an internal ADU. Utah Code 57-8a-218(16) bars HOA rules that prohibit a code-compliant internal ADU, and the state HOA Ombudsman says that covers CC&Rs too, however old they are. 57-8a-209(10) bars an HOA from restricting rental of one. A detached ADU has no such protection, so CC&Rs can restrict or bar it.

What is a specified municipality under Utah S.B. 284?

It's the set of cities S.B. 284's detached-ADU rule applies to: every city of the first, second, third or fourth class, plus a fifth-class city with 5,000 or more people in a first-, second- or third-class county (Utah Code 10-21-101). Towns and unincorporated county land are not included.

How many parking spaces can a Utah city require for an ADU?

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.