ADU rules in Salt Lake City

A single detached ADU is allowed on properties where ADUs are permitted per Chapter 21A.33 use tables; the city's ADU Handbook states this covers zoning districts where residential uses are permitted (residential, many commercial, downtown, form-based, gateway, some special purpose, and transit station zones). Not permitted in the front yard; must be behind the rear facade of the principal building if in an interior side yard, with 3 ft side/rear setbacks and a 17 ft base height limit (up to 24 ft pitched / 20 ft flat with increased setbacks).

Internal/attached ADUs (basement or existing-space conversions, additions, units above or attached to a garage) are allowed; internal ADUs must be within the buildable area and are subject to the same height requirements as the principal building.

Ordinance: no detached ADU may exceed 1,000 sq ft gross floor area; internal ADUs have no maximum provided the building complies with underlying zoning. Basements, sub-7-ft loft space, and second-story access stairs are excluded from the detached calculation. The city's ADU Handbook (v2.2) additionally says a detached ADU cannot exceed the size of the main building, a constraint not present in the current ordinance text.

Owner (or blood/marriage/adoption relative of a deeded owner, or family-trust trustor) must reside on the property, but owner occupancy is NOT required when the principal use is a duplex, multi-family dwelling, or non-residential use; temporary absences up to 3 years (military, job assignment, medical care) are also excepted. An owner-occupancy statement goes into a recorded restrictive covenant.

One parking stall required for the ADU (principal-use parking may not be reduced below its minimum), waived if: the zone has no minimum off-street parking requirement, the property already has an extra accessible stall above the principal-use minimum, the property is within a 1/4 mile radius of a public transit stop, or within 1/2 mile of a city-designated bicycle lane or path.

Permitted use requiring a building permit, a zoning certificate before occupancy, and a recorded restrictive covenant; conditional-use approval is no longer required (ADUs approved before April 4, 2023 as conditional uses are legal conforming). Historic District properties additionally need a Certificate of Appropriateness per the ADU Handbook.

An ADU shall not be rented as a short term rental (per §21A.62.040 definition), and the recorded restrictive covenant must state that neither the ADU nor the principal structure can be used for short-term rental. The Handbook FAQ describes leases under 30 days as hotel/motel/B&B uses not permitted in the relevant residential zones. Long-term rental requires a business license and enrollment in the city's landlord/tenant (Good Landlord) program.