Every homeowner considering an ADU eventually asks some version of the same question: is this actually going to be worth it? The honest answer is that it depends heavily on one thing more than any other — whether the unit is permitted. But let's start with what the broader data actually shows.
Across recent national studies, homes with a legally built ADU tend to sell for meaningfully more than comparable homes without one, with industry data citing increases in the broad range of 20-35% depending on the market. The National Association of Realtors has cited figures on the higher end of that range nationally, though markets with a more mature ADU culture (much of California, for example) tend to see the strongest and best-documented gains, since buyers there are more used to placing a dollar value on a rentable second unit.
Utah-specific data is thinner simply because ADUs are newer here than in states that have allowed them for decades. But the underlying logic — a legal second unit that can generate rental income or house family adds real, appraisable value — applies just as much along the Wasatch Front as anywhere else.
Two Utah-specific forces make ADUs particularly valuable here right now. First, the Wasatch Front has a genuine housing shortage, which means rental demand for a well-built ADU is strong in Salt Lake City, Provo, Ogden, and Park City alike. Second, multigenerational living has become increasingly common as home prices have climbed, and a private, code-compliant unit for aging parents or adult children is a feature buyers are actively searching for, not just tolerating.
This is worth repeating because it matters more than any other variable: an unpermitted ADU can actively hurt your home's value instead of helping it. Appraisers can't credit square footage or income potential they can't verify against city records, buyers' lenders may refuse to finance a purchase once an unpermitted structure is discovered, and you may be required to bring the unit up to code (or remove it) before you can sell at all. Every estimate we give includes full permitting as standard — it's not an upsell, it's the only way the added value is real and defensible.
Appraisal standards for ADUs have gotten more consistent recently, with updated appraisal datasets giving appraisers clearer guidance on how to document a second unit's contribution to value. In practice, an appraiser will typically weigh three things: comparable sales of similar properties with ADUs in your area, the unit's demonstrated or reasonably projected rental income, and the actual construction cost, particularly for higher-end custom builds.
If your primary goal is resale value, a permitted ADU is a legitimately strong investment in most Utah markets right now, but it isn't a guaranteed dollar-for-dollar return, and value gains vary by neighborhood, unit quality, and local rental demand. If your primary goal is rental income or housing family, the value question becomes secondary to whether the unit pays for itself — see our financing overview for how most Utah homeowners fund the build, and our cost breakdown for what to budget.
Either way, get a professional opinion specific to your property before treating any of these figures as a guarantee — a local appraiser or real estate agent familiar with ADUs in your specific neighborhood can give you a far more precise number than any national statistic.