A Rule Cannot Stop You From Building an ADU. Your CC&Rs Are a Harder Question.

Utah law protects internal accessory dwelling units in a community association, but only in two specific places rather than everywhere. The statute is explicit about association rules and about renting out the unit. It says nothing that names accessory dwelling units in the list of things a declaration may not do. Knowing which protection you are relying on is most of the work.

What an Internal Accessory Dwelling Unit Is

The Community Association Act does not define the term. It borrows the definition from the land use statutes, Section 10-21-101 for cities and Section 17-80-101 for counties. Three elements have to be met at once. The unit must be created "within a primary dwelling," it must sit "within the footprint of the primary dwelling" as it stands when the unit is created, and it must be created "for the purpose of offering a long-term rental of 30 consecutive days or longer."

A "primary dwelling" is a single-family dwelling that "is detached" and "is occupied as the primary residence of the owner of record." Two consequences follow that often surprise owners. A detached casita in the backyard is an accessory dwelling unit but not an internal one, so the protections on this page do not reach it. And a unit built for short-term rental does not meet the definition either, because the definition itself is written around a long-term rental.

Rules: The Protection Is Explicit

Under Section 57-8a-218(16)(a), "a rule may not prohibit the owner of a residential lot from constructing an internal accessory dwelling unit" within the owner's residential lot. That section is titled "Limits on association rules and design criteria," and this protection does what the title says: it reaches rules.

Subsection (16)(b) carries the exception. The protection does not apply if the construction would violate a local land-use ordinance, building code, health code, or fire code. The statute does not override your city or county. It prevents the association from adding its own prohibition on top of them.

Renting It Out: Also Explicit

Because the definition is built around a long-term rental purpose, the right to construct one would be worth little without the right to rent it. Section 57-8a-209(10) supplies it: notwithstanding the association's general power to restrict rentals, "an association may not restrict or prohibit the rental of an internal accessory dwelling unit" constructed within a lot owner's residential lot, if the unit complies with all applicable land use ordinances, building codes, health codes, and fire codes.

This matters most in an association that has capped rentals or banned them outright. The cap does not reach a qualifying internal accessory dwelling unit. Note the other side of it as well: Section 57-8a-102(25)(c) classifies an internal accessory dwelling unit as a rental lot, so the notice and information rules that apply to rental lots apply to yours.

The CC&Rs Are a Harder Question, and the Statute Does Not Name Them

Read the two protections above carefully, because neither one reaches a declaration. Section 57-8a-218(16) limits rules. Section 57-8a-209(10) limits rental restrictions. Neither speaks to what your CC&Rs may say about building an internal accessory dwelling unit.

The list of things a declaration may not do is in Section 57-8a-212(4), and internal accessory dwelling units are not on it. Two general entries are the closest the statute comes. Under Subsection (4)(n), a declaration may not "impose a restriction on the interior of a dwelling, except as reasonably necessary for the safety of adjacent lots and the occupants of the lots." Under Subsection (4)(k), it may not "interfere with reasonable activity of a lot owner within the confines of the lot, to the extent that the activity is in compliance with local laws and ordinances, including nuisance laws and ordinances."

Both are qualified, and the qualifiers are where the argument happens. A rule is subject to the same interior limit from a second direction. Section 57-8a-218(22)(b)(i) provides that a rule may not impose a requirement or restriction on "a dwelling's interior, except as reasonably necessary for the safety of adjacent lots and the occupants of those lots."

Submitting Plans

If your association must approve the plans, Section 57-8a-109 governs how it does so. The plan fee may not exceed the actual cost of reviewing and approving the plans. A denial must be in writing and must specify "each governing document provision on which the association relied when denying the plan," together with the specific aspect of your plan that does not conform to that provision.

A denial that gives no reason, or that cites the governing documents generally, does not meet the statute. Ask for the written specification. It also tells you exactly which provision you would need to address on a resubmission.

Where to Go Next

Start with your city or county. The association's authority is limited by the statute, but the statute defers entirely to local land-use ordinances and to the building, health, and fire codes, so a plan that does not clear those requirements never reaches the association question.

Then read your own declaration before you build, not after. Ask the board in writing whether it will treat the project as permitted and keep the answer. If the association denies your plans, ask for the written specification the statute requires.

Reviewed against the Utah Code, current as of August 12, 2026.