Summit Luxury Dwellings — ADU Education

How Much Does an ADU Cost in Utah? A Complete 2025–2026 Guide

If you've been thinking about adding an accessory dwelling unit to your property, one of the first questions you're probably asking is: how much is this actually going to cost me? It's a fair question — and one that deserves a straight answer.

ADU cost in Utah varies widely depending on the type of unit, the size, your location, and how you choose to build. In this guide we'll break down everything you need to know about ADU costs in Utah in 2025 and 2026, including what drives prices up, what keeps them down, and how homeowners across the state are getting high-quality ADUs built for under $100,000.

What Is an ADU and Why Are Utahns Building Them?

An accessory dwelling unit — commonly called an ADU, granny flat, backyard home, or in-law suite — is a secondary living unit built on the same property as a primary single-family home. It can be attached to the main house, built above a garage, or stand alone as a fully detached structure in the backyard.

Utah has seen a surge in ADU interest over the past several years, and it's easy to understand why. Housing costs across the Wasatch Front have climbed steadily, and many homeowners are looking for ways to generate rental income, house aging parents, or simply add long-term value to their property without selling and moving.

The Utah Legislature has also made it easier than ever to build ADUs — and a landmark new law is about to make detached ADUs legal statewide for the very first time.

Average ADU Cost in Utah: The Big Picture

The cost of an ADU in Utah typically falls somewhere between $80,000 and $350,000 depending on the type and method of construction. Here's a general breakdown:

As you can see, the range is enormous. The method of construction is the single biggest factor in what you'll pay — and it's where most homeowners either save or overspend.

Breaking Down ADU Costs in Utah by Type

Stick-Built Detached ADUs

A traditional site-built detached ADU is constructed from the ground up on your property using local labor and materials. This is the most expensive option, with costs in Utah typically running between $150 and $250 per square foot — sometimes more depending on your location and current labor market.

For a modest 500 square foot unit, that puts your all-in cost somewhere between $75,000 and $125,000 at the low end — and that's before accounting for site prep, permits, utility connections, and landscaping, which can easily add another $20,000 to $50,000 to your total.

The timeline is also a major consideration. Stick-built ADUs in Utah routinely take 9 to 18 months from permit approval to move-in, depending on contractor availability and weather delays.

Garage Conversions

Converting an existing detached garage into a livable ADU is one of the more affordable options, with costs ranging from $30,000 to $80,000. The savings come from the fact that the structure already exists — you're adding insulation, electrical, plumbing, HVAC, and interior finishes rather than building from scratch.

The downside is that you lose parking and storage, which matters depending on your property and local requirements. Some cities in Utah also have specific rules about garage conversions, so you'll want to check with your local planning department before moving forward.

Basement ADUs

Finishing a basement as an ADU is another cost-effective path, particularly popular along the Wasatch Front where basement homes are common. Costs typically run $40,000 to $100,000 depending on the current state of the space and the finishes involved.

Basement ADUs are internal units, which means they fall under Utah's existing state law requiring cities to permit them as a matter of right. The drawback is limited natural light and the fact that you're sharing a structure with the main home, which some renters and family members find less desirable.

Modular ADUs

This is where things get interesting for Utah homeowners who want a high-quality detached ADU without the price tag of traditional construction.

A modular ADU is built in a controlled factory environment to precise specifications, then delivered and set on a permanent foundation on your property. Because the construction happens off-site, modular ADUs are significantly faster and more cost-predictable than stick-built alternatives.

At Summit Luxury Dwellings, our modular ADU models start at $79,700 and can be delivered to your property in under 90 days. That's a fraction of the time and cost of traditional construction — without sacrificing quality or craftsmanship.

What Factors Affect ADU Cost in Utah?

Beyond the type of ADU you choose, several other variables will influence your final cost:

Site Preparation

Before any ADU can be built, your land needs to be ready. Site prep costs in Utah can range from a few thousand dollars for a relatively flat, accessible lot to $20,000 or more for properties that require grading, retaining walls, or utility extensions. If you're adding a detached ADU to an existing residential lot, you'll also need to connect to water, sewer, and electrical services — costs that vary significantly by city and proximity to existing lines.

Permits and Fees

Permit costs for ADUs in Utah vary by city. In some communities you'll pay a few hundred dollars for a straightforward permit. In others, particularly for new detached structures, you may face impact fees that can add $5,000 to $15,000 or more to your project cost. Utah state law does limit impact fees for ADUs in some circumstances, so it's worth checking with your local planning department to understand exactly what you'll owe before you commit.

Interior Finishes

Like any home, the finishes you choose will significantly affect your final cost. A functional ADU with standard fixtures, LVP flooring, and basic appliances will cost considerably less than one finished with quartz countertops, custom cabinetry, and designer tile. Budget-conscious buyers can keep finish costs reasonable while still creating a space that's comfortable, rentable, and adds genuine value to the property.

Landscaping and Exterior Work

Don't overlook the cost of restoring your yard after construction. Depending on how much of your property is disturbed during the build, landscaping and exterior work can add anywhere from $2,000 to $15,000 to your total project cost.

How Long Does It Take to Build an ADU in Utah?

Timeline is one of the most underappreciated factors in ADU planning. Every month your ADU sits unfinished is a month you're not collecting rent or using the space.

Traditional stick-built ADUs in Utah routinely take 12 to 18 months from permit approval to completion. Delays caused by contractor availability, weather, material shortages, and inspection scheduling are common.

Modular ADUs dramatically compress this timeline. Because construction happens in a controlled factory environment, weather delays and labor shortages have far less impact. At Summit Luxury Dwellings, we deliver our modular ADUs to buyer-owned land in under 90 days — meaning you could be collecting rental income this year rather than next.

Is an ADU a Good Investment in Utah?

For most Utah homeowners, a well-placed ADU is an excellent investment. Here's why:

Rental income potential is strong across Utah's Wasatch Front. A well-finished 400–500 square foot ADU in Utah County can realistically rent for $900 to $1,400 per month depending on location, finishes, and market conditions. At those rates, an ADU costing $90,000 can pay for itself in 6 to 8 years — and continue generating income indefinitely.

Property value increase is another significant benefit. ADUs generally add more value to a property than they cost to build, particularly in markets where housing supply is tight. Buyers increasingly recognize the value of a rental-ready secondary unit on a property.

Multigenerational living is a third benefit that doesn't show up in ROI calculations but matters enormously to many Utah families. Having aging parents or adult children nearby — in their own private space — is something money genuinely can't fully quantify.

For a deeper look at how an ADU can pay for itself, visit our ADU page at summitdwellings.com.

How to Finance an ADU in Utah

Financing is one of the most common questions we hear from homeowners exploring ADUs. The good news is that there are several viable paths:

• Cash purchase — the simplest option for homeowners who have equity or savings available. Modular ADUs, with their lower price points, make cash purchases accessible for more buyers than traditional construction.
• Home equity loan or HELOC — allows you to borrow against the equity in your existing home. For homeowners with significant equity this is often the most straightforward financing path.
• Construction loan — a short-term loan designed specifically for building projects. Once construction is complete, it typically converts to a standard mortgage.
• ADU-specific loan programs — increasingly available through Utah lenders, particularly as ADUs have gained regulatory and cultural acceptance across the state.

Our team at Summit Luxury Dwellings can connect you with financing resources to help you understand your options.

What Utah SB 284 Means for Your Property

Before SB 284, whether you could build a detached ADU in your backyard depended entirely on where you lived. Cities like Salt Lake City, Draper, and South Salt Lake had already embraced detached ADUs with updated ordinances. But many Utah cities — particularly in Utah County — either prohibited them outright or had no framework in place at all.

SB 284 changes that permanently. Beginning July 1, 2026, every city in Utah must allow detached ADUs on single-family residential lots as a permitted use. Cities can still set reasonable standards around setbacks, height, size, and design compatibility — but they can no longer simply say no.

For Utah homeowners, this is one of the most significant changes to residential property rights in recent memory. And for those who act before July 1, getting a modular ADU ordered and delivered now means you could be ahead of the wave of demand that's coming.

Why More Utah Homeowners Are Choosing Modular ADUs

When you compare a traditional stick-built ADU — which might cost $180,000 to $250,000 and take 12 to 18 months to complete — against a modular ADU starting at $79,700 with delivery in under 90 days, the value proposition is difficult to argue with.

At Summit Luxury Dwellings, we offer three ADU models designed specifically for the Utah market and beyond:

• The Wasatch Studio — 308 sq ft, starting at $79,700. Perfect for a single occupant, guest suite, or rental unit on a budget.
• The Teton — 425 sq ft, 1 bed/1 bath, starting at $89,700. Our most popular model, ideal for long-term rental or multigenerational living.
• The Uinta — 550 sq ft, 2 bed/1 bath, starting at $99,700. Maximum flexibility for families or higher rental income potential.

All three models are delivered to buyer-owned land across Utah and six additional western states — Nevada, Arizona, Idaho, Wyoming, Colorado, and New Mexico — in under 90 days. You can explore all three models in person at our show home in Orem, Utah, or browse specs and pricing at summitdwellings.com/models.