ADU rules in Pleasant Grove

An accessory apartment may sit in a detached accessory structure associated with a single-family dwelling, including a tiny home on a permanent site-built foundation, but only in the A-1, R-R, R-1, RM-7, DV and Grove mixed housing zones, only on an owner-occupied single-family lot, and only where the lot can supply the required off-street parking. In the R-1 zone a detached accessory structure may not exceed the height of the house or 25 feet, whichever is more restrictive, so it is held below the 35-foot main-building limit. A change is coming: Utah Code 10-21-304, enacted by S.B. 284 (2026 General Session, Chapter 166) and effective October 1, 2026, requires a specified municipality such as Pleasant Grove to permit a detached accessory dwelling unit on any lot or parcel of 11,000 square feet or larger that holds a single-family dwelling where single-family is a permitted use, and bars it from requiring a conditional use permit for one in a primarily residential zone. As of August 28, 2026 Pleasant Grove had not amended section 10-15-47 to match.

A unit within or attached to a single-family residential building (over the garage, in the basement, or in an addition) is allowed in the A-1, R-R, R-1, RM-7, DV and Grove mixed housing zones; no accessory apartment may be in any multi-family dwelling, and the lot must satisfy the parking requirement. Utah Code 10-21-303(1)(a) independently makes an internal accessory dwelling unit a permitted use in any area zoned primarily for residential use, and Pleasant Grove's zone list already covers every primarily residential district, so the two rules line up. Watch the attached-versus-detached line: Ordinance 2026-015, adopted April 14, 2026 but not yet in the published code, replaces the section 10-6-2 definition of "Building, Attached" so that only a structure physically joined by a common wall or floor to ceiling assembly counts as attached. Under the codified definition still shown online, any two buildings six feet or less apart are deemed attached.

Section 10-15-47 sets no floor-area limit for an accessory apartment. It limits occupancy instead (one person, a related family, or up to four related and unrelated persons living as a single housekeeping unit) and requires the unit to meet the zoning requirements that apply to properties in a single-family neighborhood. All 48 sections of Chapter 15 were checked and none sets an accessory-building size limit; 10-15-37 covers second kitchens, a separate topic. What does bind is height and bulk in the zone standards: in R-1 an accessory structure may not exceed the height of the dwelling or 25 feet, whichever is more restrictive. For a unit built inside the house, Utah Code 10-21-303(1)(b)(i) bars the city from regulating the size of an internal accessory dwelling unit in relation to the primary dwelling at all; from October 1, 2026 Utah Code 10-21-304(4)(b)(i) lets the city keep a detached unit from being larger than the house.

No accessory apartment may be created, established, or occupied unless the property owner occupies either a portion of the main dwelling or a detached accessory unit on the same lot. The section defines owner occupancy in detail (primary dwelling and mailing address, a named human owner of record, at least 50% recorded equity interest, special rules for trusts and limited liability companies, and a documentary burden on the claimed owner) and exempts only a bona fide temporary absence of three years or less for a job assignment, sabbatical, or voluntary service. State law backs the requirement: Utah Code 10-21-303(3)(j) lets a municipality bar the rental of an internal accessory dwelling unit that is not in the owner's primary residence, and from October 1, 2026 Utah Code 10-21-304(4)(c) lets it require the owner to live in the house or the detached unit.

Section 10-15-47(J) requires a single-family dwelling with an accessory apartment to provide four off-street spaces for the main dwelling and two for the accessory unit, six in total, counting covered parking, garages, and tandem driveway parking. No space may sit in a front or street-side setback except in an approved driveway, and surfaces must be concrete or asphalt, with limited alternatives allowed for accessory-unit spaces not directly connected to the street. Two state limits cut into that. Pleasant Grove's base standard at section 10-18-3 already requires four off-street spaces for a single-family residence, and Utah Code 10-21-303(3)(c)(i) says that where a municipality's land use ordinance requires four off-street parking spaces it may not require the additional space for an internal accessory dwelling unit, so the two extra spaces appear preempted for a unit built inside an owner-occupied detached house and rented for 30 days or longer. Separately, from October 1, 2026 Utah Code 10-21-304(3)(b) and (c) bar the city from requiring more than two on-site spaces assigned to a detached unit of 650 square feet or larger, or more than one for a smaller one. Confirm the number with Community Development before designing.

Accessory apartments are listed as a permitted principal use in the R-1 zone (use 1124 in section 10-9B-2), and approval runs through registration with the Community Development Department: a $25 fee with a registration form, site plan, and floor plans, plus a building permit for any construction, corrections identified by the chief building official, and photos of life-safety items. It is a staff-level process with no hearing described. An unregistered apartment is not legal or approved, and failure to register can bring a $500 fine that may become a lien on the property. From October 1, 2026 Utah Code 10-21-304(3)(a) will also bar the city from requiring a conditional use permit for a detached accessory dwelling unit in a primarily residential zone.

The accessory apartment shall not be intended for sale or detached by deed and shall only be rented. Occupants are limited to one person living alone, two or more persons related by blood, marriage, adoption, legal guardianship, or foster care, or up to four related and unrelated persons living as a single housekeeping unit, plus a temporary guest staying under 30 days in any rolling year. The city sets no minimum lease term and, in its 2024 moderate income housing report, told the state it does not require a business license to rent an accessory dwelling unit. State law leaves room for a stricter rule the city has not adopted: Utah Code 10-21-303(3)(i) lets a municipality bar rentals of an internal unit shorter than 30 consecutive days, and from October 1, 2026 Utah Code 10-21-304(4)(b)(iv) will let it bar rentals of a detached unit shorter than 90 consecutive days.