Accessory dwelling units, the basement apartments, converted lower levels, and backyard units that add a second home to a single-family lot, sit at the center of Utah’s housing-supply debate. Since 2021, state law has limited how much cities can restrict one specific kind: the internal ADU. For a homeowner thinking about a rental unit or an investor underwriting a property’s income potential, the gap between what state law guarantees and what a city can still regulate is where most of the confusion lives. This brief explains what the internal ADU statute permits as of 2026, what local governments retain control over, how internal and detached units differ, and how to confirm your own city’s current rules. This is general information, not legal advice. ADU rules change at both the state and city level. Confirm specifics with your city planning department and the current Utah Code before relying on them.
What HB 82 requires: internal ADUs as a permitted use
Utah’s 2021 ADU law, passed as HB 82 and codified at Utah Code 10-9a-530, made the internal accessory dwelling unit a permitted use in most residential zones. An internal ADU is one created within the footprint of an existing single-family home, such as a basement or lower-level apartment, rather than a separate structure in the yard. “Permitted use” is the key legal phrase. It means a qualifying internal ADU is allowed by right in the covered residential zones, so a city cannot require a discretionary public hearing or a conditional-use approval to permit one that meets the standards. The law was designed to add long-term rental housing inside existing homes without the case-by-case approval process that had blocked many units before. The statute pairs that permission with a set of limits cities are allowed to impose, which is where local control comes back in.
What cities can still regulate
HB 82 did not hand homeowners an unconditional right. It set the baseline and then enumerated the conditions a municipality may attach. As of 2026, cities may generally:
- Require one additional off-street parking space for the internal ADU, and require that converted garage parking be replaced.
- Prohibit internal ADUs in a limited share of residential land. The statute lets a city restrict them in up to roughly a quarter of the area zoned primarily for single-family residential use, along with certain other carve-outs.
- Require a rental license or permit and basic registration.
- Apply building, health, and safety codes, including egress, fire separation, and inspection requirements.
- Limit occupancy and set the unit as a long-term rental, with internal ADUs defined as rentals of 30 days or more, which effectively excludes short-term or nightly rentals.
One widely misunderstood point is owner occupancy. HB 82 removed the statewide mandate that the owner live on site for an internal ADU, but it did not forbid cities from keeping an owner-occupancy condition. Many Utah cities have retained an owner-occupancy requirement, so an investor planning to rent both the main home and the ADU should verify whether the specific city still requires the owner to live in one of the units.
Internal versus detached ADUs
The statewide permitted-use protection is narrower than many homeowners assume, because it applies to internal units, not detached ones. A detached backyard unit can still be allowed, encouraged, or restricted entirely depending on the city, because the state’s by-right protection centers on internal units. An investor or homeowner weighing a detached unit should treat the local ordinance as controlling rather than assuming the statewide rule applies.
How the rules keep changing and why 2026 matters
Land-use law in Utah has been an active area for the legislature, and ADU and zoning provisions have been revisited in multiple recent sessions as the state pushes on housing supply. That means the precise contours, which zones are covered, the exact percentage of land a city may exempt, and the conditions a city may attach, can shift from year to year. The practical consequence for 2026 is that you should not rely on a city ordinance or a summary that predates the current session, and you should not rely on a neighboring city’s rules as a proxy for your own. Two cities in the same county can implement the state baseline differently within the latitude the statute allows. Confirm the current state statute text and your city’s adopting ordinance before you design, permit, or underwrite a unit.
How to confirm your city’s current ADU rules
A short verification sequence covers most of what an owner or investor needs.
- Read the current statute. Start with Utah Code 10-9a-530 for the internal ADU baseline and any recent amendments.
- Pull your city’s ADU ordinance. Cities adopt their own implementing ordinance within the state framework; the planning or community-development department publishes it.
- Confirm the four local variables: parking, owner-occupancy, rental licensing, and whether your parcel sits in an area where internal ADUs are restricted.
- Ask about detached units separately, since they fall outside the statewide by-right protection.
- Verify building and safety requirements with the building department: egress windows, ceiling height, fire separation, and a separate entrance.
Frequently Asked Questions
Are ADUs legal in Utah?
Internal accessory dwelling units, those built inside an existing single-family home such as a basement apartment, are a permitted use in most residential zones statewide under HB 82 (Utah Code 10-9a-530). Detached ADUs are not guaranteed statewide and depend on the city’s ordinance.
Does Utah require the owner to live on the property to have an ADU?
State law removed the statewide owner-occupancy mandate for internal ADUs, but it allows cities to keep one. Many Utah cities still require the owner to occupy the main home or the ADU, so check your specific city’s ordinance.
Can I rent my Utah ADU on Airbnb?
Internal ADUs under HB 82 are defined as long-term rentals of 30 days or more, which generally excludes nightly or short-term rentals. Short-term rental rules are governed separately by city ordinance and can be restrictive.
How many parking spaces does a Utah ADU require?
Cities may require one additional off-street parking space for an internal ADU and may require replacing garage parking that is converted. The exact requirement is set by your city within the limits the statute allows.
What is the difference between an internal and a detached ADU in Utah?
An internal ADU is created within the existing home’s footprint and carries statewide permitted-use protection under HB 82. A detached ADU is a separate structure on the lot and is subject to local discretion, often requiring conditional-use approval and additional standards.
That’s the lay of the land on Utah ADUs as of 2026. The statewide rule is real but narrow: it protects internal units, leaves detached ones to your city, and lets cities attach conditions like parking and owner-occupancy, so the local ordinance is what you actually build against. None of the above is legal advice, and these rules move, so check the current statute and your city before you commit. We’re a licensed Utah brokerage, so if you’re weighing what an ADU does to a property’s value or eventual sale, homie.com/sell is where we live.
— The Homie Team
- Utah Code 10-9a-530 (Internal Accessory Dwelling Units)
- Utah Legislature, bill tracking
- Salt Lake County, Accessory Dwelling Units
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