A bigger pool of lots
Moving from half an acre to the state ceiling of a quarter acre could open the option to many more Mapleton homeowners.
Mapleton, Utah
Mapleton: from half an acre toward a quarter acre.
Mapleton's earlier code required 21,780 square feet, a half acre, for a detached accessory apartment. The City Council voted this year to amend its ADU code to comply with state law, which caps the lot size a city can require at 11,000 square feet.
ADU code amended in 2026
What we confirmed for Mapleton
Source: Mapleton City Code (pre-amendment); local council coverage; Utah Code 10-21-304.
- Before
- Detached accessory apartments needed a lot of 21,780 sq ft (half an acre)
- State ceiling
- A city cannot require more than 11,000 sq ft for a detached ADU
- Council action
- Voted unanimously to amend the ADU code and keep its size limits by lot size
- Special areas
- The Harvest Park subdivision keeps an existing exemption
- Removed
- A 40 percent limit on ADU size
Not confirmed: The exact lot-size threshold in Mapleton's adopted code and its size caps by lot size. Confirm both with Mapleton before you spend money on plans.
What it means for you
What changes for Mapleton homeowners.
Size depends on the lot
Mapleton kept size limits tied to lot size, so a larger lot may allow a larger unit.
Check your subdivision
Some subdivisions, including Harvest Park, have their own rules and covenants.
Plans that fit
Compact floor plans for a Mapleton backyard.
Small plans are easier to fit inside setbacks and cap parking at one space under 650 square feet. Open any plan for photos and the floor plan.
Final fit depends on your lot, utilities, the delivery route and the city's current standards. We confirm all of it in a lot review.
Budget the site work before you fall for a plan.
The home is only part of what a detached ADU costs. Sewer, water and power connections, trenching, the foundation and the finish work that joins the modules add up, and they depend on how far your lot is from the utilities. Taylorsville city staff told their council that utility connections alone could run 50 to 70 percent of the cost of a detached unit. We price the site and the utilities line by line in a lot review, before you commit to a plan.
How to plan the full budgetHow 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 plans and site information Mapleton will want for approval and the 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
Mapleton ADU questions.
Does SB 284 apply to Mapleton?
Yes. Mapleton is covered by the state mandate, which requires a covered city to allow a detached ADU on a lot of 11,000 square feet or more that has a single-family home, as a permitted use. Cities can still set size, height, setback, owner-occupancy and rental rules within the limits of the law. Read the SB 284 guide.
How much parking does a detached ADU need?
A city cannot require more than one on-site space for a detached ADU under 650 square feet, or more than two for a unit of 650 square feet or larger.
Can I rent it out?
The state allows a city to require rentals of at least 90 consecutive days and to require the owner to live on the property. Check how Mapleton applies those rules to your lot.
What if my lot is smaller than 11,000 square feet?
The state mandate does not reach it, but a city may choose to allow smaller lots. Ask Mapleton Planning what applies to your parcel.
Does Stoneward work in Mapleton?
Yes. Stoneward is based in American Fork and serves Utah County and the rest of the Wasatch Front. We run a lot review first and tell you plainly if a detached ADU does not fit.
General information, not legal advice. Cities can amend their ordinances, so confirm current rules with Mapleton before you design or buy.
Own a lot in Mapleton?
Send us your address. We will check the lot against Mapleton's rules and tell you honestly whether a detached ADU fits.