Eagle Mountain, UT Accessory Structures: ADU Rules (2026)

EMMC 17.70.030(A) caps every residential lot at a maximum of one accessory dwelling unit, whether it sits within an owner-occupied single-family dwelling or in a separate detached accessory structure. EMMC 17.70.030(C) requires the ADU to conform to all applicable International Fire Code and International Residential Code standards, and EMMC 17.70.030(D) lists where an ADU may go: within or attached to the main dwelling, over an attached or detached garage, or in a detached accessory structure such as a cottage home, casita, or guest house, subject to the zoning-district rules in EMMC 17.25.030.

Detached ADUs carry their own dimensional standards under EMMC 17.70.030(D)(3). Height is capped at 35 feet, and a unit above a garage may not exceed that height either; standalone detached units may not exceed two stories or 35 feet. The living space of a detached ADU must fall between 400 and 1,200 square feet, may not exceed two bedrooms, and must be permanently connected to utilities on a site-built permanent foundation that complies with the building code, with a building permit and inspections required for the foundation, the structure, and its utility connections. Detached ADUs must also meet the same front, side, and rear setbacks as the primary dwelling, sit at least six feet from that primary dwelling, and the lot must have at least 70 feet of street frontage, though a smaller-frontage lot can be approved at the discretion of the approval authority in unique circumstances.