ADU Cost in Utah: What You Will Actually Pay in 2026

An ADU in Utah costs $60,000 to $400,000 or more in 2026. The type of ADU drives that price the most. A basement or garage conversion reuses a foundation you already have. That keeps the cost near the low end. A detached backyard unit needs its own foundation. It also needs its own utility lines and its own permit review. That makes it the most expensive type. Your city's rules also decide if a detached unit can even go on your lot.

Below is what each type costs. You will also see what Utah law and your city require. Last, you will see how to tell if your lot can fit a detached unit.

How Much Does an ADU Cost in Utah in 2026?

Here is what the four main types of ADU cost in 2026, based on a published Utah ADU cost guide. These are market ranges, not a Uintah Builders quote.

• Internal or basement ADU: $60,000 to $150,000+ ($100 to $250 per square foot). Reuses space and a foundation you already have.
• Garage conversion: $60,000 to $175,000+ ($125 to $275 per square foot). Reuses the garage's existing foundation and roof.
• Attached addition: $150,000 to $275,000+ ($225 to $375 per square foot). Ties a new room into your existing home.
• Detached backyard ADU: $200,000 to $400,000+ ($250 to $450 per square foot). A freestanding small home with its own foundation, from the ground up.

Call or text (619) 815-7695 for a free written estimate once you know which type fits your lot.

Why Does the Type of ADU Change the Price So Much?

The foundation is the biggest reason. A basement or garage conversion starts with a foundation that already exists. It already passed inspection once. A detached ADU does not get that head start. South Jordan's design rules call for footings at least 30 inches deep. The framing must also handle Seismic Zone D and 115 mph wind loads. That means real digging, concrete, and strong connectors before the walls even go up.

The second reason is utility lines. A basement or attached unit can often use the main home's water, sewer, and power. The two spaces already share walls or a foundation. A detached unit sits out in the yard. It usually needs its own trenched utility lines. That adds cost before any framing starts. This is also why a garage conversion often costs less than an attached addition. The garage already has a slab, a roof, and nearby utility hookups. The crew is finishing something that exists, not building from scratch.

Do You Need a Permit for an ADU in Utah?

Yes, in every city in Utah. The exact steps depend on where you live and what you build. A 2021 state law, Utah House Bill 82, covers internal ADUs. It requires every city to allow one internal ADU inside an owner-occupied home. Cities must allow it by right. A city cannot block it based on your lot size or your street frontage.

The state law does leave a few things up to the city. A city can require one extra parking space for the ADU. A city can also bar a separate utility meter for it. A city can require that the ADU not change how the home looks from the street.

That state law covers internal ADUs only. Detached ADUs still follow each city's own rules. South Jordan, where Uintah Builders is based, allows both internal and detached ADUs under the city's ADU Guide. One of the two units on the property must stay owner-occupied. If you plan to rent the ADU, South Jordan requires an ADU permit through its Online Development Portal. If you will not rent it, a notarized form takes the place of that permit. Either way, South Jordan reviews the plans under the current building code. Uintah Builders pulls the permit and handles the inspections. You do not have to track down city paperwork.

Is a Detached ADU Allowed on Every Lot?

Legally allowed is not the same as realistic. A detached ADU needs a side or back yard big enough for setback rules, plus room for the unit itself. Lot size varies a lot across the Salt Lake Valley. Newer cities like Bluffdale and Eagle Mountain tend to sit on bigger lots. Older, tighter lots are more common closer to Salt Lake City and in South Jordan's original neighborhoods.

Bluffdale's median home value is $685,500, the highest among the cities Uintah Builders serves. Eagle Mountain's is $518,100, the most affordable of the Utah County cities the company serves. Newer construction explains part of that gap. 92% of Eagle Mountain's homes were built in 2000 or later. 56% of Bluffdale's homes were built in 2010 or later. Those newer subdivisions generally have bigger lots than older infill areas. If your lot is tight, a basement conversion or a garage conversion is often the more realistic choice.

Is an ADU Worth It in Utah?

Most homeowners build an ADU for one of three reasons: rental income, a place for aging parents, or extra space for a grown child. All three reasons need the build done right the first time. An ADU with permit or inspection problems cannot legally be rented or lived in.

Owner Juan Vazquez brings 25 years of hands-on building experience to our new construction and ADU team. The crew handles the full build, from permits to finish. Uintah Builders is licensed, bonded, and insured. Every ADU comes with a 5-year workmanship warranty.

Does a detached unit not fit your lot? A garage conversion or room addition is often the more affordable path to the same extra space. Converting your garage instead walks through that option in detail. For a bigger project, compare an ADU against building a new home from the ground up. South Jordan homeowners can also see the permit and inspection steps the city requires.

Get a Real Number for Your ADU

Your lot, your city's rules, and the ADU type you pick all move the final number more than any national average can. Uintah Builders walks your lot, checks what your city will allow, and gives you a written price before any work starts. One crew handles the whole job, from the foundation through framing, electrical, plumbing, and finish work.

Contact Uintah Builders for a free written estimate on your ADU.

Related service: New Construction