A new Utah law that took effect October 1, 2026, requires many of the state's larger municipalities to permit detached accessory dwelling units (ADUs) on qualifying lots of 11,000 square feet or more. According to a October 23 report by Best Utah Real Estate, the law, passed as S.B. 284, opens possibilities for garage apartments in neighborhoods where detached units were previously restricted.
The mandate applies to specified municipalities, including cities of the first through fourth class, and fifth-class cities with populations of 5,000 or more in larger counties. This includes Wasatch Front locations such as West Valley City and West Jordan. While the law allows for detached units, it includes specific caps on parking requirements: cities cannot require more than two on-site spaces for a detached ADU of 650 square feet or larger, or more than one space for a smaller unit. Additionally, in primarily residential zones, a city cannot classify a detached ADU as a conditional use.
Despite the state mandate, cities maintain significant regulatory authority. Local governments may prohibit detached ADUs that are larger than the main house, keep them out of front yards, or limit each lot to a single ADU. Cities can also require owners to live in either the main house or the ADU, ban rentals lasting less than 90 consecutive days, and require replacement parking if a detached garage is converted. Standard rules regarding structure size, height, and lot coverage also remain applicable.
Salt Lake City has established different standards, having approved an ADU ordinance on April 4, 2023, which maintains an owner-occupancy requirement. The city does not utilize the 11,000-square-foot threshold and allows units up to 1,000 square feet that do not exceed the size of the main building. Height limits in Salt Lake City are generally 17 feet, though this can increase to 24 feet with a pitched roof if setbacks are increased. The city also offers a pilot loan program for properties west of I-15, providing up to $200,000 at a 3% fixed rate for ADU construction.
The push for expanded housing comes amid significant demand and rising costs. The Kem C. Gardner Policy Institute's September 2026 housing report noted that Utah's median sale price reached $520,000 in the first quarter of 2026, up from $500,000 the previous year. The institute estimates Utah will require approximately 280,000 additional housing units by 2035 to meet demand, including 98,000 units for households headed by individuals aged 65 or older.
