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Utah Statewide Rule

Utah Internal ADU Statewide Preemption Law

Few RestrictionsApplies statewide across Utah (2026)

Key Facts

Statute
Utah Code 10-9a-530
ADU Type Required
Internal only
Owner Occupancy
Required
Effective Year
2021
Last verified: September 5, 2026Source: Utah State Legislature

Summary

Utah Code 10-9a-530 requires municipalities to allow internal accessory dwelling units in owner-occupied single-family homes. Cities cannot ban internal ADUs but may regulate parking, design, and registration. The 2021 law substantially preempts local prohibitions on ancillary in-home rentals.

(1) In any area zoned primarily for residential use: (a) the use of an internal accessory dwelling unit is a permitted use; (b) except as provided in Subsections (2) and (3), a municipality may not establish any restrictions or requirements for the construction or use of one internal accessory dwelling unit within a primary dwelling, including a restriction or requirement governing: (i) the size of the internal accessory dwelling unit in relation to the primary dwelling; (ii) total lot size; (iii) street frontage; or (iv) internal connectivity; and (c) a municipality's regulation of architectural elements for internal accessory dwelling units shall be consistent with the regulation of single-family units, including single-family units located in historic districts.

Source: Utah State LegislatureView official code

Full Breakdown

Utah Code Section 10-9a-530 mandates that every municipality permit at least one internal ADU as a use by right within an owner-occupied primary single-family dwelling located in a residential zone. Cities may impose reasonable standards including a single off-street parking space, owner-occupancy, prohibition of short-term rentals under 30 days, and registration requirements, but cannot outright ban internal ADUs. Detached ADUs remain subject to local zoning discretion. Counties have parallel authority under 17-27a-526. The law was passed in 2021 to expand housing supply across Utah while preserving neighborhood character through narrowly defined regulatory limits.

Violations & Penalties

Municipal denial of compliant internal ADU permits may result in legal challenge and attorney fees. Property owners violating registration or occupancy conditions face local code enforcement.

Frequently Asked Questions

Can my Utah city prohibit internal ADUs?
No. Utah Code 10-9a-530 requires cities to allow at least one internal ADU as a permitted use in owner-occupied single-family homes located in residential zones, subject only to reasonable standards.
Are detached ADUs protected by state law?
No. Only internal ADUs (within the primary home) receive statewide protection. Detached or accessory-structure ADUs remain subject to full municipal zoning authority and may be banned locally.
Can cities ban short-term rentals of internal ADUs?
Yes. Utah law expressly allows municipalities to require that internal ADUs not be rented for periods shorter than 30 consecutive days, preventing nightly vacation rental use.

Sources

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