Layton, UT Accessory Structures: ADU Rules (2026)

300, "Accessory Dwelling Unit Standards," governs ADUs citywide as an accessory use within all single-family residential zones. 020(4). Internal and attached ADUs are treated as part of the primary dwelling for zoning purposes, so they must meet that dwelling's own minimum setback and height limits rather than separate accessory-structure standards, and their design must keep the overall building looking like a single-family home; the ADU's entrance has to be subordinate to the primary entrance rather than presenting as a second front door. The city also folds ADUs into the same infrastructure as the main house: all utility connections, water, gas, sewer, and similar lines, must tie into the primary dwelling's service, and the ADU cannot carry its own separate street address; both units share one address number that has to be visible from the street.

Interior access between the main living area and an internal or attached ADU must stay open unless the fire department's inspection finds sufficient separate egress. Every ADU, whether internal, attached, or detached, needs its own building permit obtained before construction or occupancy, and mobile homes, RVs and shipping containers are explicitly disqualified from counting as an ADU under the ordinance.