ADU Permits Utah: What You Need Before You Build or Rent
In Utah, assume you need local approval before you build, convert, legalize, or rent an accessory dwelling unit (ADU) — a second, self-contained living unit on a single-family property. State law protects many internal ADUs (a unit inside your existing home), and a new state rule for detached ADUs (a separate backyard unit) takes effect October 1, 2026. But local approval is always required, and the exact approvals you need depend on your ADU type, your city or county, your lot, and what you plan to do with the unit.
The most important thing to understand: "state law allows more ADUs" does not mean "my exact ADU can be built or rented without local approval." It usually can't.
Last verified: June 2026.
About this guide. Utah ADU Builders is an independent Utah ADU planning, feasibility, and builder-matching resource — not a city office, government agency, law firm, lender, architect, engineer, licensed contractor, or permit authority. We may earn compensation when homeowners request a feasibility review or are connected with local professionals. That never changes how we describe Utah's ADU rules, cost ranges, feasibility factors, or local permitting risks.
Which ADU permit path are you probably dealing with?
The single most useful thing to know is which type of ADU you're trying to permit, because the approval path changes completely. Find your situation below, then read the section that matches it.
| Your ADU situation |
|---|
| Basement / internal ADU (inside your existing home) |
| Attached ADU / addition (connected to your home) |
| Detached ADU / backyard cottage (separate structure) |
| Garage conversion |
| Existing or unpermitted unit (legalizing what's already there) |
The most common mistake is assuming "state law allows more ADUs" means "my exact ADU can be built or rented without local approval." It usually can't. A quick feasibility check on your address can help identify which path you're likely on before you spend money on plans.
What we verified (June 2026)
- • Utah state law — the Utah Office of Property Rights Ombudsman's ADU summary and Utah Code §§ 10-21-303 (cities), 17-80-303 (counties), and 10-21-304 (detached ADUs, effective October 1, 2026)
- • City and county ADU pages and ordinances — Salt Lake City, Salt Lake County (unincorporated), Provo, Millcreek, Murray, Draper, Cottonwood Heights, Ogden, North Salt Lake, and Lehi
- • Local permit and process pages — application steps, required documents, and licensing
- • Contractor licensing — Utah's licensing framework and the DOPL license-verification lookup
What we did not do: provide legal, tax, financing, architectural, or engineering advice, or guarantee any permit approval, fee, timeline, rental income, or property-value outcome. Cost and timeline figures are estimates that vary by city and project. Local verification is required — especially through late 2026, while Utah's detached-ADU rules and city ordinances are still moving.
Do you need a permit for an ADU in Utah?
Yes. Assume any ADU in Utah needs local approval before you build, convert, legalize, or rent it. State law can limit how cities regulate certain ADUs — especially internal ones — but it does not make ADUs permit-free or exempt from building, fire, health, parking, utility, or rental rules.
Salt Lake County, for example, requires a building permit before you construct or convert an ADU. Salt Lake City requires a building permit and may require a separate site review, business license, and recorded covenant before you can legally rent. Draper requires a valid ADU permit before any ADU — internal or detached — may be rented or offered for rent.
The state ADU laws protect certain ADU types from outright prohibition — but they are not a substitute for local permit approval. "Legal under state law" and "permitted at my address" are not the same thing.
ADU permits Utah homeowners may need: building, zoning, and rental approvals
"Getting a permit" can actually mean several separate approvals, and which ones apply depends on your city and the scope of work. If no construction is needed to create the unit, the key approval may be a rental license rather than a building permit; if you're building or converting, expect a building permit on top of that.
Depending on your city and project, you may encounter:
- •A building permit for construction or conversion work.
- •A land-use, site-plan, zoning, or ADU permit that confirms the unit is allowed on your lot.
- •A rental dwelling license, business license, or zoning certificate before you can legally lease it.
- •Inspections and in some cities a recorded affidavit or covenant tying the property to owner-occupancy or rental rules.
Permission to build is not always permission to rent
This is a key trap. Final building approval does not automatically mean you can rent the unit. Many Utah cities regulate rental licensing, owner occupancy, and lease length separately — and short-term rentals are often restricted or banned. Plan the rental approval as its own step, not an afterthought.
What type of Utah ADU are you permitting?
The permit path depends on the ADU type. A basement conversion inside your home follows a different, usually simpler, route than a new detached cottage, a garage conversion, an attached addition, or an existing unit you're trying to legalize.
| ADU type |
|---|
| Internal ADU |
| Basement apartment |
| Attached ADU |
| Detached ADU |
| Garage conversion |
| Prefab / modular ADU |
A few quick definitions you'll see throughout:
- Owner occupancy:
- The property owner must live on the property — usually in either the main home or the ADU.
- Setback:
- The minimum distance a structure must sit from a property line.
- Impact fee:
- A one-time charge some cities collect on new construction to fund roads, parks, utilities, or emergency services.
- Utility hookup:
- The connection (and sometimes a separate meter) for water, sewer, gas, or electricity.
- Short-term rental:
- Generally means a stay under 30 days; ADU rules often require longer terms.
- Egress:
- A code-compliant emergency escape — for a basement bedroom, usually a properly sized egress window.
Internal ADU permits in Utah: what state law protects
Utah law gives internal ADUs a protected status in most residential areas, but you still have to meet building, health, fire, and local administrative requirements. An internal ADU is generally a long-term rental unit created within the footprint of an owner-occupied, detached single-family home.
What the state protects — and what cities still control
Under Utah's internal-ADU law — summarized by the Utah Property Rights Ombudsman and codified at Utah Code § 10-21-303 (municipalities) and § 17-80-303 (counties) — an internal ADU is a permitted use in areas zoned primarily for residential use, and the unit must comply with building, health, and fire codes. That "permitted use" status means a qualifying internal ADU generally cannot be prohibited outright.
What cities generally cannot do
- Prohibit internal ADUs outright in primarily residential zones
- Charge impact fees on internal ADUs within the existing primary dwelling
- HOAs generally cannot prohibit renting a qualifying internal ADU where it wouldn't violate local code
What cities can still require
- •One additional off-street parking space
- •Owner occupancy
- •A permit or license to rent
- •Prohibition on short-term (under 30-day) rentals
- •No change to the home's exterior appearance
- •No separate utility meters
- •Restrictions in limited zones (≤25% of residential area, or up to 67% for cities with a large university)
The internal-ADU impact-fee point (read this carefully): According to the Utah Office of Property Rights Ombudsman, construction of an internal ADU within the existing primary dwelling is not subject to impact fees. That's a real advantage for basement-style conversions. But do not extend it: detached ADUs, additions, utility upgrades, and various city-specific fees can still apply.
Detached ADU permits in Utah: the new rule taking effect October 1, 2026
A new detached-ADU provision takes effect October 1, 2026. Detached units — separate backyard structures — have historically been left almost entirely to local cities, and many didn't allow them. Under Utah Code § 10-21-304 (enacted by SB 284 in the 2026 General Session), a "specified municipality" must permit a detached ADU on qualifying lots once the rule takes effect.
What Utah Code § 10-21-304 requires
Beginning October 1, 2026, a "specified municipality" must allow a detached ADU as a permitted use on any lot that is at least 11,000 square feet and already contains a single-family home, in a zone where single-family homes are permitted. "Specified municipality" covers most incorporated Utah cities (first- through fourth-class cities, plus fifth-class cities of 5,000 or more in larger counties). The smallest towns and unincorporated county land may not be covered.
A covered city may NOT
- ✕Require a conditional use permit (must be a permitted use)
- ✕Require more than one on-site parking space for a detached ADU under 650 sq ft
- ✕Require more than two parking spaces for one 650 sq ft or larger
A covered city must also provide a path to convert a legally built accessory structure (like an existing detached garage) into a detached ADU, subject to setbacks and building, health, and fire codes.
A covered city MAY still
- ✓Set size, height, lot-coverage, and setback standards
- ✓Require the ADU to match the design of the main home
- ✓Require owner occupancy
- ✓Prohibit renting for less than 90 consecutive days (higher bar than the 30-day internal-ADU floor)
- ✓Prohibit a detached ADU larger than the main home
- ✓Prohibit in front yards, easements, or where utility capacity is inadequate
- ✓Allow detached ADUs on lots smaller than 11,000 sq ft (the 11,000 sq ft is the state floor, not a cap)
Why your city's page might not match the new rule yet
Ordinances are catching up at different speeds. Lehi, for instance, has publicly stated it is amending its code to meet the state detached-ADU requirement, referencing the 11,000-square-foot threshold; Provo has published its own implementation guidance. That's exactly why an address-specific check matters right now: a backyard ADU that was prohibited at your lot may become allowed under the new rule — but your city's own forms and standards may still be catching up.
Utah city-by-city ADU permit snapshot
ADU permits are local. State law sets the floor, but the practical answer depends on the city or county reviewing your application — and whether your property sits inside city limits or in unincorporated county territory. The examples below show how much the details vary. Always confirm current rules for your exact address.
| Jurisdiction |
|---|
| Salt Lake City |
| Salt Lake County (unincorporated) |
| Provo |
| Millcreek |
| Murray |
| Draper |
| Cottonwood Heights |
| Ogden |
| North Salt Lake |
| Lehi |
City rows last checked: June 2026. City rules and fee schedules change — especially anything about detached ADUs, which are being revised in 2026 — so confirm your exact address before relying on any row.
Sources: Salt Lake City, Salt Lake County, Provo, Millcreek, Murray, Draper, Cottonwood Heights, Ogden, North Salt Lake, Lehi.
What documents do Utah cities usually ask for?
Most Utah ADU permits require more than a simple form. Cities commonly ask for a site plan, floor plan, building plans, owner verification, a parking layout, and utility information — and sometimes elevations or water-provider confirmation. Gathering these early prevents delays and rejected submittals.
A typical document set includes:
Millcreek lists an ADU checklist, a property-owner affidavit, a site plan, elevations, and a floor plan among its application materials; Ogden requires a site plan, floor plans, and ownership/residency verification; and Salt Lake County notes water-provider confirmation before a permit is issued.
Utah ADU permit steps: from feasibility to final approval
The cleanest path is not "design first, ask questions later." In Utah, the safer sequence is feasibility, a rule check, an ADU-type decision, permit-ready plans, local review, inspections, and rental approval if you'll lease the unit.
- 1Confirm jurisdiction. City limits versus unincorporated county can change the entire permit path.
- 2Identify your ADU type. Internal, attached, detached, garage conversion, prefab, or an existing unit you're legalizing.
- 3Screen the state-law and city-law issues. Owner occupancy, lot size, parking, setbacks, utility access, rental duration, HOA/CC&Rs, and short-term-rental limits.
- 4Check physical feasibility. Egress, ceiling height, fire separation, plumbing, sewer, electrical service, drainage, access, and structural needs.
- 5Prepare permit documents. Site plan, floor plan, elevations, construction plans, affidavits, utility documentation, and contractor information where required.
- 6Submit the local application and building permit. Salt Lake City, for example, uses an online permit and plan-review process — the technical review where building, zoning, utilities, fire, and other departments check your plans against code — with the departments involved depending on the project's scope.
- 7Respond to corrections. Corrections are normal. They can involve zoning, utilities, fire separation, egress, parking, structural details, or missing documents.
- 8Complete inspections. Inspections and a final sign-off are usually required before legal occupancy.
- 9Complete the rental/licensing step if you'll rent. Some cities require a rental dwelling license, business license, zoning certificate, affidavit, or recorded notice before leasing.
What can block or slow down an ADU permit in Utah?
An ADU is not automatically a smart project just because Utah has become more ADU-friendly. The right project depends on your lot, city, utilities, budget, and use case — and several common issues can stall or sink an application before construction even starts.
If several of these apply to your property, the honest answer may be that an ADU isn't the right move yet — or that a different ADU type or scope is the smarter path. A feasibility review is designed to surface that before you've spent on design.
How much do ADU permits cost in Utah?
There is no single statewide ADU permit fee. Permit-stage costs can include an application fee, a building-permit fee based on project valuation, a plan-review fee, utility-related charges, impact fees on some detached ADUs, and rental or business-license fees. The figures below are estimates to set expectations — your actual costs depend on your city and project.
| Permit-stage cost |
|---|
| Design / construction drawings |
| Building permit fee |
| Plan-review fee |
| ADU / land-use / site-plan fee |
| Impact fees |
| Utility connection fees |
| Rental / business license |
The biggest "surprise" line on detached projects is usually impact and utility fees. For full project budgeting beyond permits, see our Utah ADU cost guide.
How long do ADU permits take in Utah?
Timing depends on the city, the ADU type, how complete your plans are, how many correction rounds you go through, utility review, and inspections. Internal ADUs often have fewer site-plan, setback, and detached-structure issues than detached ADUs — but cities may still require ADU applications, permits, inspections, licensing, zoning certificates, affidavits, or recorded notices. Detached new construction usually takes longer because it adds a site review on top of a fuller plan review. Some cities publish a target for their first plan-review pass, but that is not the same as a guaranteed full ADU approval timeline.
What tends to add time:
- •An incomplete application or a missing site plan or floor plan
- •Engineering requirements or utility review
- •Zoning, parking, or setback corrections
- •Fire- or building-code corrections
- •A separate rental-licensing step after construction
- •A city actively updating its ADU ordinance
For a fuller look at construction timing, see our Utah ADU build-timeline guide.
Can you rent the ADU after the building permit is approved?
Not always. In many Utah cities the building-permit path and the rental-approval path are connected but not identical. After construction you may still need a rental dwelling license, a business license, a zoning certificate, an owner affidavit, a recorded notice, or proof that your lease term meets local ADU rules.
A short-term rental warning
Do not assume you can use a Utah ADU as a short-term rental. Many ADU rules are built around long-term tenancy, and cities frequently restrict short stays:
- Draper requires ADU leases of at least 30 consecutive days.
- Murray prohibits short-term rentals for ADUs.
- Millcreek allows long-term rental with compliance and licensing steps, while short-term rules differ by ADU type.
- Internal-ADU law specifically lets local governments prohibit rental periods under 30 days.
- Detached ADUs (new 2026 rule) lets a city prohibit rentals shorter than 90 consecutive days — a higher bar than the internal-ADU 30-day floor.
If rental income is your goal, confirm the lease-length and licensing rules before you design. For more, see our Utah ADU rental-income guide.
What if the basement apartment or ADU already exists?
An existing basement kitchen, side entrance, garage conversion, or backyard unit is not automatically a legal ADU. Legalizing it usually means checking zoning, permit history, building/fire/health code, parking, owner occupancy, and rental licensing — and confirming whether the necessary corrections are even possible.
This is where unpermitted units get expensive. The costliest mistake is often not the finishes — it's assuming a space is "fine" because it looks like an apartment. Problems commonly surface at the worst moment:
If you bought a home where an agent said the "mother-in-law apartment" was legal, don't assume that's true. Cities are increasingly asking owners to verify and, where needed, bring existing units into compliance — and an egress or safety gap can turn a rental into a liability.
If the answer turns out to be "no," you can still finish a beautiful basement — you just can't represent or rent it as a second dwelling without meeting the rules. A feasibility review can tell you whether your existing unit is likely fixable.
Do you need a licensed contractor for an ADU permit in Utah?
Often, yes — and some cities require it outright. Many full ADU construction permits require a licensed contractor because the work involves structural, electrical, plumbing, mechanical, or life-safety systems. Murray's ADU page, for example, explicitly states that owner-builder is not permitted and a licensed contractor is required. Some limited situations may differ — such as a no-construction change-of-use path, or small work that doesn't involve mechanical, electrical, or plumbing systems — depending on your city's rules and Utah licensing law. Utah's Division of Professional Licensing (DOPL) offers a public license-verification lookup so you can confirm any contractor's status yourself.
Before you hire, verify:
- DOPL license status (active, in good standing)
- The right general or specialty trade license for the work
- Insurance
- ADU experience in your specific city or county
- Whether the contractor will be listed on the permit documents
- Who handles plan corrections and inspections
- Whether the estimate includes utility upgrades, permits, fees, and code corrections — not just the structure
We don't describe builders as "verified," "pre-vetted," or "approved" anywhere on this site unless we publish the exact standard behind that word and it's true. When you're ready, we help you compare practical build options and connect with local professionals — and you can still confirm any license independently through DOPL.
ADU permit-readiness checklist (before you ask for estimates)
Before you request builder estimates, gather the information that determines whether your ADU is likely feasible. This prevents the common mistake of comparing quotes for a project that may need a different design, a different ADU type, or more local review than you expected.
Property basics
- Address and jurisdiction (city vs. county)
- Lot size
- Zoning, if known
- HOA or CC&R restrictions, if any
- Existing home type
Project type
- Internal / basement ADU
- Attached ADU
- Detached ADU
- Garage conversion
- Prefab / modular ADU
- Existing-unit legalization
Rental / use plan
- Family or parent housing
- Long-term rental
- Short-term rental (check local limits)
- Office / studio
- Owner-occupancy plan
- Future resale flexibility
Physical feasibility
- Parking
- Separate entrance
- Egress windows
- Ceiling height
- Sewer location
- Water service
- Electrical panel capacity
- Setbacks and easements
- Drainage / slope
Permit readiness
- Existing plans or sketches
- Photos of the proposed space or site
- Prior permits for a finished basement or garage
- A plan to verify contractor licenses through DOPL
- Budget range
- Timeline goal
How Utah ADU Builders helps with ADU feasibility
We help Utah homeowners figure out whether an ADU idea is worth exploring before they pay for plans or request estimates. Our instant-estimate path starts with feasibility, gives you a practical cost direction, and then helps you compare next-step build options if the project looks worth pursuing.
To be clear about what this is and isn't: our feasibility and cost tools are not a permit approval, a legal opinion, a construction bid, a financing approval, or a guarantee of rental income or property value. Local verification is still required before you build or rent. What we offer is a faster, lower-risk way to find out which path you're on — and whether to take the next step at all.
Related Utah ADU resources
Frequently asked questions
Sources consulted (June 2026)
City rules and fee schedules change; this guide is rechecked on a recurring schedule and should be re-verified after October 1, 2026.
- Utah Office of Property Rights Ombudsman — ADU summary
- Utah Code § 10-21-303 — Internal ADUs (cities)
- Utah Code § 17-80-303 — Internal ADUs (counties)
- Utah Code § 10-21-304 — Detached ADUs (eff. Oct 1, 2026)
- SB 284 — 2026 General Session
- Salt Lake City ADU code (§ 21A.40.200) and permit pages
- Salt Lake County — unincorporated ADU page
- Provo — ADU pages and SB 284 implementation notice
- Millcreek — ADU page
- Murray — ADU page
- Draper — ADU permits page
- Cottonwood Heights — ADU page
- Ogden — ADU code
- North Salt Lake — ADU page
- Lehi — Detached ADU code amendment
- Utah DOPL license-verification lookup
Ready to check what your property can actually support?
Find out which ADU type is likely feasible at your address, what it may cost, and what permit path you're probably on — before you pay for plans or request estimates.
Start Your Free ADU Feasibility Check →No address, no credit check, no commitment required.