Planning commission recommends backyard cottage rules to meet state deadline
September 16, 2026, 6:30 p.m. · American Fork City Hall, 31 N. Church St.
The American Fork Planning Commission unanimously recommended rules for detached accessory dwelling units, the backyard homes that a new state law requires cities to allow on single-family lots of at least 11,000 square feet by Oct. 1. Commissioners added changes: required parking must be off-street on the same lot with no tandem spaces, units may go in side yards without a variance, and they must sit at least 10 feet from the main house. The commission also approved a site plan for National GMC at 629 E. 1000 South that eliminates a landscape strip along I-15.
From the draft minutes.
Decisions at a glance
| Item | Result |
|---|---|
| National GMC Addition commercial site plan, 629 E. 1000 South | Approved · 7-0 |
| "A" definitions: accessory buildings, dwellings and structures (Section 17.12.201) | Recommended for approval · 7-0 |
| "D" definitions: detached accessory dwelling unit (Section 17.12.204) | Recommended for approval · 7-0 |
| Detached accessory dwelling unit regulations (new Section 17.5.136) | Recommended for approval · 7-0 |
Agenda, item by item
Item 5a · Development
National GMC Addition commercial site plan, 629 E. 1000 South
Approved · 7-0
Site improvements to the existing 4.71-acre National GMC dealership in the GC-2 zone. The only outstanding issue was the applicant's request to reduce the required 6-foot perimeter parking-lot landscape strip to zero along the north/northeast side next to I-15, where there is no landscaping now and an existing wall separates the lot from the freeway. Staff supported the reduction, saying it adds pavement for circulation and fire access and avoids an unused area needing weeding and water; Chair Christine Anderson and Commissioner Rodney Martin agreed. The commission found the intent of the landscaping rule was met and approved the site plan.
- Acres: 4.71
- Zone: GC-2
- Landscape strip reduced from 6 feet to 0 along I-15 (Section 17.5.121)
- No other conditions of approval
Item 5b · City code
"A" definitions: accessory buildings, dwellings and structures (Section 17.12.201)
Recommended for approval · 7-0
Staff-initiated definitions to remove ambiguity between accessory buildings, accessory dwellings and accessory structures, in preparation for detached ADU rules. No public comment.
- Initiated by: city staff
Item 5c · City code
"D" definitions: detached accessory dwelling unit (Section 17.12.204)
Recommended for approval · 7-0
Staff-initiated definition of a detached accessory dwelling unit. No public comment.
- Initiated by: city staff
Item 5d · City code
Detached accessory dwelling unit regulations (new Section 17.5.136)
Recommended for approval · 7-0
Patrick O'Brien said Utah Code 10-21-304 requires cities to allow detached ADUs on single-family lots of 11,000 square feet or more, with limits on what cities may regulate, and the city must have rules in place by Oct. 1. The draft sets setbacks, height, maximum size, location, materials (no galvanized, corrugated or ribbed metal facades), parking (one added stall for units up to 600 square feet, up to two for larger units), owner occupancy of one of the two units, a 90-day minimum rental to bar short-term rentals, utility capacity and fees, and administrative review by the Development Review Committee; a lot may have an internal or a detached ADU but not both. Commissioners added: parking must be off-street on the lot (no right-of-way, no cross-parking agreements), no tandem parking, DADUs allowed in side yards without a variance if setbacks are met, a 10-foot wall-to-wall separation from the main house, and a typo fix. Commissioner Harold Dudley voiced reservations about side-yard units. The City Council adopted the ordinance 4-0 on Sept. 22.
- Initiated by: city staff
- State law: Utah Code 10-21-304; deadline Oct. 1, 2026
- Eligible lots: single-family, 11,000 sq ft or more
- Minimum rental: 90 days
- Commission changes: off-street parking on same lot, no tandem parking, side yards allowed, 10-ft separation from home
- Council adopted Ordinance 2026-09-21 on Sept. 22, 4-0 (Councilmember Clark Taylor absent)
What residents said
No one spoke during public comment or at the three public hearings on accessory dwelling rules. Under other business, Patrick O'Brien announced the opening of Rancho Market, a new grocery store in a previously vacant commercial unit, with a grand opening set for Sept. 26.