Can you build an ADU for aging parents in Utah? (2026 guide)

Families rarely arrive here through a construction project. They arrive because a parent is struggling with stairs, or living alone three hours away, and the only option on the table is a facility nobody wants. A backyard home is the third option: a parent keeps a front door, a kitchen and their own bed, and you are sixty feet away instead of thirty minutes.

What does an ADU cost compared to assisted living in Utah?

Cocoon's 300 Series, a true one bedroom with a full kitchen, full bath and laundry, is typically $84,000 for the home. Built on a foundation in your backyard, with site work, utility connections and city fees, most land at $113,000 to $126,000 all-in. Plan on the home price plus 35 to 50 percent for everything that happens on your lot; we break that down on our Utah ADU cost page.

Assisted living in Utah has a median cost of $5,475 a month, or $65,700 a year, according to CareScout's 2025 Cost of Care Survey (the survey Genworth has run since 2004). That payment never stops, and it rises most years.

So a backyard ADU costs about what 21 to 23 months of assisted living costs. The difference is what you have at the end of those two years: the facility has your money, and the ADU is still standing in your yard.

Does Utah law actually let me build one?

For a lot of families, it just became legal where it was not before. Utah S.B. 284, now Utah Code 10-21-304, took effect October 1, 2026. In the cities the law covers, which includes the larger Wasatch Front cities, a detached ADU must be allowed on any lot of 11,000 square feet or larger that holds a single-family home, as long as the single-family home is itself a permitted use there. In a primarily residential zone, a covered city cannot make you go through a conditional use permit for it.

Cities kept real authority, and that is where projects get decided. The statute lets a city cap you at one ADU per lot, require the owner to live in either the main house or the ADU, prohibit rentals shorter than 90 consecutive days, keep the ADU smaller than the main house, and regulate setbacks, height, size and lot coverage. A city may also deny a build where sewer, water or power capacity is not there.

The owner-occupancy rule matters more than families expect here. Salt Lake City, Draper, Lehi, Murray, Herriman, Highland, Pleasant Grove, Eagle Mountain and West Valley City all require the owner to live in one of the two units. If you own the house and your parent lives in the ADU, you are fine. If the plan was for your parent to own the ADU while you rent out the main house, check your city first. Our city-by-city rules tracker covers 34 Wasatch Front cities and was last reviewed October 6, 2026.

Which floor plan fits a parent living on their own?

Four of our five plans work for one person or a couple. The deciding factor is usually how much of their old life they are bringing with them.

The 300 Series at 300 square feet is what most families choose: a separate bedroom with a door, a full kitchen with full-size appliances, a real bathroom with a choice of tub or shower, and laundry in the unit. Typically $84,000. The separate bedroom is the part that matters. A studio stops feeling like home when it is where someone spends most of the day.

The 200 Series at 240 square feet is a smaller one bedroom with a kitchenette, typically $73,000, for a parent who still eats most meals with the family. The 400 Series at 400 square feet, typically $94,000, adds a flex second room that families use for a live-in caregiver or grandchildren staying over. The 500 Series is a true two bedroom at 500 square feet, typically $109,000, and the usual pick when both parents move in. Compare all five plans here.

One structural point worth knowing: because a Cocoon ADU is built on-site on your foundation by our own Utah crew, it is not held to the 10-foot width a road-towable home is. A wider plan means wider hallways and more turning room, which is the most useful accessibility decision you can make early.

What should the unit have if someone is going to age in it?

Build for the parent your parent will be in ten years, not the one picking finishes today. These are the choices to settle at the plan stage, when they cost the least, because every one of them is expensive to retrofit:

• A zero-step entry, so a walker and later a wheelchair gets in without a ramp bolted on afterward.
• Wider doorways and hallways. 36-inch doors are the standard worth asking for.
• Blocking inside the bathroom walls, so grab bars mount into structure later without opening the wall.
• A curbless shower rather than a tub to climb into. Every 300 Series comes with a choice of tub or shower, so this is a decision, not an upgrade fight.
• Lever handles instead of round knobs, which arthritis makes genuinely difficult.
• Good lighting at every transition, because most falls at home happen where the light changes.

Tell us at the first conversation which of these you want and we will plan the home around them. Personalizing a standard plan carries no design fee; a fully custom layout with stamped construction plans runs $7,000 to $10,000. For ADUs, Cocoon submits the plans to the city.

What happens to the ADU afterward?

Families hesitate to ask this out loud, and it deserves a straight answer: eventually the ADU will not be housing your parent. A facility room has no second life. A permanent dwelling on your property does.

It becomes a rental. A one-bedroom backyard ADU on the Wasatch Front typically rents for $1,200 to $1,500 a month, and we work the payback math by city here. Or it becomes a guest house, an office, or where an adult child lands for a year. Check your city's rule on rentals under 90 days before counting on short-term income. It is also why the first comparison understates the case: the ADU stops costing money the day it is finished.