Utah County cities prepare for statewide detached ADU changes
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- The Salem Park neighborhood is pictured from Spanish Fork on Friday, Aug. 15, 2025.
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- The interior of an accessory dwelling unit is shown Wednesday, April 1, 2026.
S.B. 284 passed by the state legislature this year limits how municipalities may regulate detached accessory dwelling units, forcing cities to amend their existing policies by Oct. 1.
The policy change will have an immediate impact on Utah County cities, potentially making thousands of additional properties eligible to have backyard housing units.
The law allows detached ADUs on parcels of 11,000 square feet or larger that contain a single-family dwelling in a permitted use area.
Cities cannot require conditional permits on DADUs or impose maximum sizes on DADUS, but may prohibit them from being larger than the primary home. Cities may not require more than two on-site parking spaces for detached ADUs 650 square feet or larger, and the DADU structures must meet building codes.
To what extent the new law impacts the existing policies of Utah County’s largest cities varies.
Lehi already allowed DADUs on lots with minimum sizes of 14,520 square feet, capping detached dwelling sizes at 1,300 square feet. Orem did not allow DADUs, and Provo allowed DADU’s in specific overlay zones where internal and external ADU allows are allowed.
The cities are also on varying timelines to implement new policies.
On Tuesday, the Lehi City Council approved its new policy, which stipulates the DADU must be 6 feet from the existing home and requires owner occupancy of either the primary or detached dwelling.
During the council meeting, Lehi Community Development Director Kim Struthers estimated the number of DADU eligible units could increase by upwards of 20%.
“It’s not insignificant by any means,” he said.
Lehi resident Holly Rollins told the council her home qualifies for a DADU under the new change and said her family plans to build a backyard home for her ailing parents.
“We’re just looking for a way to help provide care while also allowing my parents to be independent, but being close enough that we can help them out,” she said.
Orem discussed its DADU changes in a city council work session Tuesday, and the planning commission was scheduled to hear the amended code proposal Wednesday night.
Orem proposed policy will stipulate that DADUs are not allowed in the front yard and cannot be short-term rentals, according to city assistant development services director Gary McGinn.
“We’re trying to look at things where we can have good common sense regulation that protects existing neighborhoods while meeting state law requirements,” McGinn told the council Tuesday.
In Provo, the City Council has discussed the issue in work meetings, but it has yet to come before the planning commission or the council for a vote. Provo council staffer Rachel Breen told the Daily Herald the council is still hearing out how the new laws will impact the city.
In a June 9 council work session, policy analyst Melia Dayley proposed that all accessory structures on a lot may not cover more than 40 percent of the total parcel area. Provo also published a map that shows projected new ADU eligibility.
