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American Fork, Utah
Backyard ADUs are now allowed in American Fork.
American Fork adopted detached ADU rules on September 22, 2026, to meet Utah's new SB 284. If you own a lot of 11,000 square feet or more, a factory-built home in the backyard may now be an option. Stoneward is based right here in American Fork.
American Fork's rules at a glance
As adopted by the City Council on September 22, 2026 (4 to 0).
- Lot
- At least 11,000 sq ft, with an existing detached single-family home
- Footprint
- Up to 1,500 sq ft or the main home's footprint, whichever is smaller
- Height
- No taller than the main house, and no more than 24 ft
- Setbacks
- 12 ft on most sides and rear, 20 ft on the street side of a corner lot
- Yard coverage
- ADU plus other accessory buildings: 25% of the rear yard open space at most
- Parking
- 1 space under 650 sq ft, 2 spaces at 650 sq ft or more
- Occupancy
- Owner lives in the main home or the ADU, one ADU per lot
- Rentals
- 90 consecutive days or longer
The city also requires building, health and fire code compliance, adequate utility service and capacity, and Development Review Committee review. The council said it will revisit parking, height and impact fees, so confirm current rules with American Fork City.
What it means for you
A new option for American Fork homeowners.
Until this fall, an American Fork homeowner could add an apartment inside the house but not a separate unit in the yard. A detached ADU can give you a place for family, a long-term rental, or a home office or studio, without giving up your main home.
Long-term rental income
Rentals of 90 days or more are allowed, and you must live on the property. It is worth running the numbers before you commit, and we will help.
Smaller is easier
Under 650 sq ft means one parking space, and a small footprint is easier to fit inside the setbacks and the 25 percent yard limit.
Short disruption
A factory-built unit is built off site and set by crane, so your yard is a work zone for weeks, not many months.
Plans that fit
Floor plans that suit an American Fork backyard.
These stay under or near the 650 square foot parking line and have compact footprints. Open any plan for photos and the floor plan.
Final fit depends on your lot, the main home's footprint, utilities and the delivery route. We confirm all of it in a lot review.
How it works here
From your lot to move-in.
- Lot review. We check lot size, setbacks, utilities and the delivery route to your backyard.
- Choose a plan and finishes. Pick a floor plan and one of four finish series.
- City review. We help you prepare the submittal for American Fork's Development Review Committee and building permit.
- Foundation and utilities. Site work happens on your lot while the home is built in the factory.
- Delivery and set. The home arrives by truck and is set by crane, then finished, connected and walked through with you.
Questions
American Fork ADU questions.
Can I build a detached ADU in American Fork?
Yes, if your lot qualifies. The City Council adopted detached ADU rules on September 22, 2026, ahead of the October 1 state deadline. The lot must be at least 11,000 square feet with an existing detached single-family home on it. American Fork already allowed internal accessory apartments, but backyard units were new.
How big can an American Fork detached ADU be?
Under the adopted rules the footprint cannot exceed 1,500 square feet or the footprint of the main home, whichever is smaller. The unit also cannot be taller than the main house or exceed 24 feet.
How close to the property line can it sit?
Most side and rear setbacks are at least 12 feet, rising to 20 feet on the street-facing side of a corner lot. The ADU and other accessory buildings together cannot cover more than 25 percent of the open space in the rear yard.
How much parking is required?
One on-site space for a unit smaller than 650 square feet, and two for a unit of 650 square feet or more, including exactly 650. That is one reason many of our plans under 650 square feet work well here.
Do I have to live on the property?
Yes. The owner must live in either the main home or the ADU. Only one accessory dwelling unit is allowed per lot, and the backyard unit cannot be rented for fewer than 90 consecutive days.
What is the approval process?
The unit must meet building, health and fire codes, have adequate utility service and capacity, and go through review by the city's Development Review Committee. Talk to American Fork Development Services early, and we will help you assemble the plans and site information they will want.
Could the rules change?
Yes. The council passed the ordinance to meet the state deadline and said it would revisit parking, height and infrastructure and impact fees. Check with the city for the current text before you finalize a design.
Does Stoneward work in American Fork?
Yes. Stoneward Construction is based in American Fork and serves Utah County, Salt Lake County and the rest of the Wasatch Front.
General information based on the ordinance as adopted September 22, 2026. It is not legal advice, and the city may amend its rules.
Own a lot in American Fork?
Send us your address. We will check the lot against the city's rules and tell you honestly whether a detached ADU fits.