League outlines 'Option D' for detached ADUs and previews MIHP 2 in state housing plan talks

The Utah League of Cities and Towns’ Local Policy Committee on Aug. 25 reviewed a draft approach to statewide policy for detached accessory dwelling units and an early framework for a second iteration of the Modern Income Housing Plan.

League staff asked members to focus on “Option D,” a draft model that would require municipalities to adopt ordinances allowing detached ADUs while preserving local flexibility on most technical items. Under the draft, DADUs would be a permitted use (not a conditional use permit) and the state would establish baseline objectives — including a suggested starting lot size of 10,000 square feet for eligibility — while leaving details such as setbacks, parking, unit size limits and business licensing to local ordinances. Staff said larger MIHP-designated cities (population 5,000+) would have a shorter implementation runway than smaller jurisdictions.

“Cities shall have an ordinance that allows detached ADUs,” staff said when introducing the option, but added that cities could deny a DADU application where an ordinance clearly documents “insufficient infrastructure.” The draft retains owner-occupancy as a potential state default while noting some cities may allow both units to be rented.

Members raised operational concerns. Mark Christiansen of Saratoga Springs asked whether cities would be forced to allow both internal and detached ADUs on the same lot and warned of parking and utility impacts. League staff replied that the draft lets cities decide whether to permit an internal ADU and a detached ADU on one parcel, but that the ordinance would need to spell out the approach. Staff also emphasized the importance of allowing local ordinances to define ‘‘sufficient infrastructure’’ as a condition to deny new units.

The committee reviewed three technical questions posed via Slido: a proposed minimum detached-ADU setback of 5 feet from adjacent properties (where utility easements are clear), whether state law should require both internal and detached ADUs on a lot if one unit is owner-occupied, and how impact fees should be calculated (options included counting a DADU as less than one equivalent residential unit, creating a DADU-specific user fee, or conducting a DADU-focused impact-fee study).

Carson, a member of the housing technical committee, said the state housing plan’s technical committee has focused on four metrics the committee believes are best measured at the local level: the number of housing units built and planned within designated centers; documented infrastructure deficiencies and system improvement costs; approval timing (being piloted with volunteer cities rather than imposed statewide); and certificates of occupancy as a production metric, which staff said could be reported through modern income housing plan reports.

The committee also previewed MIHP 2, a proposed update intended to make strategies more concrete (offering safe-harbor actions), simplify and shorten reporting so compliance can be verified more quickly, and explore creation of a new state revenue stream to reward cities that adopt stronger policies rather than penalize those that do not. Staff emphasized that no final funding mechanism has been chosen.

Next steps: staff will run member Slido responses back to the advisory subgroup for tweaks, and the League’s housing advisory subgroup will meet again in late August and September ahead of Commission on Housing Affordability and legislature deadlines. The League asked members to submit local case studies and to volunteer for pilot reporting on approval timing if their city is willing to share milestones.