Utah ADU Parking Requirements: What Homeowners Need to Know
Utah ADU parking requirements depend on the ADU type and your city or county. For an internal ADU — a second living unit built inside your existing home, like a basement apartment — state law lets your city or county require at most one extra on-site parking space, and none if it already requires four off-street spaces for the house. For a detached ADU — a separate backyard structure — your local government sets the rule, with new statewide limits beginning October 1, 2026. This guide is for homeowners checking whether parking is a problem before they pay for plans or bids.
Last verified: July 2026. Next scheduled review: October 2026.
Quick terms, defined once
- ADU (accessory dwelling unit):
- A second, self-contained living unit on a single-family lot.
- Internal ADU:
- Created inside the existing home’s footprint (e.g., a basement apartment). This is the type Utah state law protects most directly.
- Detached ADU:
- A separate structure — a backyard cottage or a standalone garage apartment.
- Attached ADU:
- A new addition with its own entrance, attached to the house.
- Off-street / on-site parking:
- Usually a qualifying space on your property (driveway, garage, or a paved pad) rather than the curb — but whether a specific driveway, garage, tandem, or gravel space actually counts depends on your local ordinance.
- Tandem parking:
- One car parked directly behind another.
Utah ADU parking requirements by project type
Find your situation. This is the fast version; the details and city-by-city rules are below.
| Your situation | Practical parking answer | What to check next |
|---|---|---|
| Internal ADU / basement apartment | State law lets your city or county require up to one additional on-site space — and none if it already requires four off-street spaces for the house. | Your local rule; whether your driveway/garage already counts. |
| Garage or carport conversion | Higher risk: if the ADU removes parking the home is required to have, you may have to replace it. | Whether the garage currently counts toward required parking. |
| Attached ADU (addition) | Usually reviewed like a regular ADU plus normal residential parking rules; some cities scale spaces to bedroom count. | Your city’s rule; setbacks and lot coverage. |
| Detached ADU — before Oct 1, 2026 | Your city’s current ordinance controls. Requirements vary a lot. | City code, lot size, driveway access. |
| Detached ADU — on/after Oct 1, 2026 | In covered cities, the state caps it at 1 space (unit under 650 sq ft) or 2 spaces (650 sq ft or larger). | Whether your city is covered and how it updated its code. |
| Relying on street parking | Don’t assume it counts. Many Utah cities require the space to be on your property. | Your city’s exact wording. |
What Utah state law says about internal ADU parking
For internal ADUs, Utah does not erase local parking review — it caps it. State law lets a city or county require one additional on-site parking space for an internal ADU, but it also removes that power in a specific case and adds one for garage conversions.
Internal ADUs are a permitted use. Under Utah Code § 10-21-303 (municipalities) and § 17-80-303 (counties) — the rules first created by HB 82 in 2021 and renumbered in the state’s 2025 land-use code overhaul — a qualifying internal ADU is allowed by right in most residential zones. (If you still see the old citation “10-9a-530” on other sites, that’s the prior number for the same municipal rule.)
The parking rule and its limits
- Standard rule:A city or county may require one additional on-site parking space for the internal ADU, on top of what the home already needs.
- Exception:If the local ordinance already requires four off-street parking spaces for the home, the local government may not tack on the extra internal-ADU space.
- Garage/carport conversions:If you create the internal ADU inside a garage or carport that becomes living space, your city or county may require you to replace the parking you removed.
Two things worth underlining. First, this is a ceiling on local government, not a mandate on you — a city can require fewer than one space, and some do. Second, “on-site” generally means on your property, but cities differ on whether your existing driveway or garage counts toward that space, so the local wording matters (more on that below).
Sources: Utah Code § 10-21-303; § 17-80-303; Utah Department of Commerce, Office of the Property Rights Ombudsman.
Detached ADU parking and the October 1, 2026 update
Detached ADUs have their own, newer set of rules — and a date you need to know. As of mid-2026, a homeowner planning a detached ADU is in a transition period: today the city’s ordinance controls, but a statewide change to detached-ADU parking takes effect October 1, 2026.
What changes on October 1, 2026
Utah’s 2026 detached-ADU law (SB 284, adding Utah Code § 10-21-304) requires many Utah cities — the statute calls them “specified” municipalities — to allow detached ADUs as a permitted use in certain zones, and it limits how much parking those cities can require:
- No more than one on-site parking space for a detached ADU smaller than 650 square feet.
- No more than two on-site parking spaces for a detached ADU 650 square feet or larger.
Covered cities must also allow detached ADUs on qualifying lots (generally 11,000 square feet or larger). On size, a covered city can require the detached ADU to be no larger than the main home — but it still controls setbacks (the required distance from property lines), height, lot coverage, design compatibility, owner occupancy, and where the parking sits within the caps above.
Sources: Utah SB 284 (2026 General Session); Utah Code § 10-21-304; City of Lehi planning (Engage Lehi) implementation notice.
Utah ADU parking requirements by city
Because detached and attached ADU parking is decided locally, the requirement depends on where you live. The table below summarizes rules we verified from each jurisdiction’s official code, ADU page, or application, with the source noted. Use it as a planning snapshot — the city or county reviewing your permit controls the final interpretation, and zone, lot shape, and overlays can change the answer.
Last verified: July 2026.
| Jurisdiction | ADU parking rule | Watch out for | Source |
|---|---|---|---|
| Utah — state baseline (internal ADU) | City or county may require up to 1 extra on-site space; none if the home already needs 4 off-street spaces. | Converting a garage can trigger replacement parking. | Utah Code § 10-21-303 / § 17-80-303 |
| Utah — state baseline (detached ADU), from Oct 1, 2026 | Covered cities: no more than 1 on-site space (under 650 sq ft) or 2 (650 sq ft or larger). | Applies to “specified” cities on qualifying lots (generally 11,000+ sq ft); confirm your city’s adopted code. | Utah Code § 10-21-304 |
| Salt Lake City | 1 space per ADU — waived near transit (within ¼ mile of a stop), near a city bike lane/path (within ½ mile), in no-minimum-parking zones, or if a spare stall already exists. | The home’s required parking can’t drop below its minimum to make room. | SLC Code 21A.40.200 |
| Provo | A home with an ADU must have at least 4 off-street spaces. | Front-yard driveway parking is allowed only under set conditions and can’t sit between the house and the street. | Provo Code 14.30.030 |
| Ogden | Keep the home’s required 2 off-street spaces; tandem parking in the driveway is allowed within limits. | No new front/side-yard parking pad or widened driveway just for the ADU. | Ogden Code 15-13-39 |
| West Jordan | 1 extra 9′×18′ paved (asphalt or concrete) space; no tandem; can’t block the home’s parking; 2 spaces must remain in the existing garage/carport. | Detached (“external”) ADUs are limited to lots larger than 10,000 sq ft; the driveway leading to the garage doesn’t count as the ADU space. | West Jordan Code 13-5B-8 |
| Draper | At least 1 extra on-site space for both internal and detached ADUs; parking may not be tandem (directly behind another space). | Detached ADUs allowed on lots ≥12,000 sq ft; internal on lots >6,000 sq ft. | Draper City ADU page |
| Millcreek | At least 1 off-street stall; no ADU parking on the street. A garage conversion is allowed only if the lot fits an added space for the ADU and the garage parking is replaced with at least one covered stall. | Detached ADUs require a lot ≥8,000 sq ft and must sit in the rear yard. | Millcreek City ADU page |
| South Ogden | Required ADU stalls may not sit in the front-yard setback; garage/carport spaces count. | — | South Ogden Ord. 23-21 |
| South Salt Lake | At least 1 additional space; more spaces are required by bedroom count for additions/attached ADUs and external (detached) ADUs. | A second driveway for ADU access requires a circular connection with 35 ft between entrances. | South Salt Lake City ADU page |
| South Jordan | At least 1 off-street space; can’t block the home’s required parking. | The Daybreak community uses its own standards (ADUs only above a detached or semi-detached garage). | South Jordan ADU Guide |
| Lindon | Internal: 1 off-street stall. Detached or substantially attached: 4 total off-street stalls (2 for the home + 2 for the ADU). | Hard, dustless surface and a walkway are required; converted garage/carport spaces must be replaced. | Lindon Code 17.46.100 |
| West Bountiful | 1 extra off-street space; garage and driveway space may count; hard surface or gravel allowed. | If the ADU is in a garage/carport, you must replace that parking. | West Bountiful Code 17.82.040 |
| Salt Lake County (unincorporated) | At least 1 on-site space in addition to the home’s required parking. | Detached ADU lots must be at least 7,000 sq ft (6,000 sq ft in the PC zone). | Salt Lake County ADU page |
If your city isn’t listed, local verification is required before you design, permit, or build — rules differ even between neighboring cities. The fastest way to get a parcel-specific answer is a feasibility check, not a guess from a nearby city’s rules.
Can driveway or tandem parking count for a Utah ADU?
Sometimes — but this is one of the most city-specific parts of ADU feasibility, so “I have a long driveway” is not a safe assumption. Cities disagree on whether the driveway counts and whether tandem parking is allowed.
Driveway parking
In some cities a driveway space can satisfy the requirement if it meets local standards; in others it can’t. West Jordan is a good example of the strict end: the ADU space must be a separate 9′×18′ paved pad, and the driveway leading to the garage doesn’t count. West Bountiful is more flexible, allowing garage and driveway space to count. The space often has to be hard-surfaced (concrete, asphalt, or pavers), and many cities cap how much of the front yard can be paved.
Tandem parking
Ogden allows tandem parking in the driveway within limits — one car behind another. West Jordan does the opposite and prohibits tandem for the required ADU space, and Draper prohibits tandem for both internal and detached ADU parking. Lindon allows tandem in a side yard for a detached unit. So the same driveway can pass in one city and fail in another.
Blocking the home’s parking
A common rule across cities is that the ADU space can’t reduce or block the parking the main house is required to have. West Jordan spells this out and also requires two spaces to remain in the existing garage. This is exactly why narrow driveways and garage conversions get complicated.
Does street parking count for an ADU in Utah?
Don’t assume it does. Many Utah cities use “on-site” or “off-street” language, which points to a space on your property rather than the curb — and some say it outright. Millcreek, for instance, requires at least one off-street stall and states plainly that ADU parking is not allowed on the street. Salt Lake City’s rules center on providing a stall on the property, with waivers near transit rather than a reliance on the street.
Street parking may be perfectly legal for general use in your neighborhood and still not count toward your ADU permit. Snow routes, overnight restrictions, narrow streets, and HOA rules can add friction on top of that. The safe framing: street parking may be available near you, but confirm your city’s ADU ordinance before you assume it satisfies the requirement — and don’t build a plan around it.
What if you’re converting a garage or carport into the ADU?
Garage and carport conversions are the highest-risk parking scenario, because they can remove parking the home is required to have. Utah state law specifically allows local governments to require replacement parking when an internal ADU takes over garage or carport space, and cities apply this in different ways.
- West Jordan requires that at least two spaces remain in the existing garage, and an attached garage generally can’t be converted unless the required two-car garage is replaced.
- Millcreek allows a garage conversion only if the lot can fit an added space for the ADU and the garage parking is replaced with at least one covered stall.
- Lindon and West Bountiful both require you to replace any garage or carport spaces you convert.
- Draper requires another garage — attached or detached — if you enclose the garage to create an internal ADU.
Practical options if a conversion creates a parking problem
- Add a legal, hard-surfaced off-street space elsewhere on the lot.
- Reconfigure or widen the driveway, if your city allows it.
- Use rear or alley access, where available.
- Choose a basement/internal ADU instead of a garage conversion.
- For a detached ADU, keep the unit under 650 square feet where the post–October 2026 cap is lower.
- Keep part of the garage as parking, and confirm the main home still meets its own parking minimum.
Utah ADU parking feasibility checklist
Before you request estimates, gather the parking facts a designer, feasibility reviewer, or city planner will need. This is the difference between a productive first conversation and paying for a plan that fails on parking.
Bring these answers
- Your city or county (this decides most of the rules)
- Your ADU type: internal, basement, garage conversion, attached, or detached
- How many legal off-street/on-site spaces you have now
- Whether your garage/carport currently counts toward required parking
- Whether the ADU would remove a garage/carport space
- Whether the proposed space is paved or hard-surfaced and meets your city’s size (often 9′×18′)
- Whether any space would be tandem (and whether your city allows it)
- Whether the ADU space would block the home’s required parking
- For detached ADUs: is the unit under or over 650 square feet, and is your lot large enough?
- In Salt Lake City: is your property near a transit stop or city bike path (possible waiver)?
- Whether an HOA or recorded CC&Rs could add restrictions your city doesn’t
Where you likely land
What if your property doesn’t meet the parking rule?
A parking problem doesn’t always kill the ADU — but it can change which ADU is right for you. The lowest-risk next step is figuring out whether you need a layout change, a different ADU type, a smaller detached unit, a waiver path, or a site-specific review.
Paths that often work
- Add a compliant on-site space.
- Switch from a garage conversion to a basement/internal ADU.
- Switch from a detached ADU to an attached or internal one.
- Shrink a detached ADU to stay under the 650-square-foot parking threshold after October 2026.
- Keep the garage for parking and build the ADU elsewhere.
- Use a waiver where it exists — for example, Salt Lake City’s transit/bike-proximity waiver.
- Pause if a parking redesign makes the project impractical.
Parking is only one piece of ADU approval
Even if parking works, your ADU still has to clear other rules. Keep these on your radar (they’re covered in more depth on our related guides):
- Owner occupancy — Many Utah cities require the owner (or, in some cities, an immediate family member) to live in either the main home or the ADU. It’s a common condition, but it varies by city.
- Short-term rentals — An ADU approval does not automatically allow nightly rentals. Many Utah cities restrict ADU rental length separately, typically requiring stays of 30 days or more.
- Permits and safety — Parking compliance never replaces building permits, inspections, egress, fire separation, and utility requirements. Salt Lake County, for instance, requires a building permit and compliance with building, fire, and health codes before an ADU is occupied.
Related Utah ADU guides
Utah ADU Laws (2026)
Full breakdown of state law, SB 284, and city authority.
Utah ADU Owner Occupancy Requirements
Who must live on the property and how cities define it.
ADU Permits Utah
What permits, fees, inspections, and approvals to expect.
Detached ADU Builders Utah
Backyard cottage options, costs, and how to vet builders.
Prefab ADU Utah
Modular and prefab options, lead times, and site requirements.
Salt Lake County ADU Guide
Rules and lot requirements for unincorporated county residents.
Frequently asked questions
What we verified
For this guide (verified July 2026), we checked: