ADU rules in North Salt Lake

ADUs are allowed in a detached accessory structure (cottage home, guest house, tiny home, or above a detached garage) in any zone on a single-family lot, subject to owner occupancy and setback, parking, and lot coverage standards. They are not allowed on multi-family lots. North Salt Lake (about 23,474 residents, a fourth-class city) is a specified municipality under Utah Code 10-21-304, in force since October 1, 2026, which requires cities to permit a detached ADU on any single-family lot of 11,000 sq ft or more; the city code already goes further by allowing detached ADUs on single-family lots of any size, and the city had not adopted a separate 10-21-304 ordinance as of October 20, 2026.

ADUs are allowed within or attached to the main dwelling (basement or addition) or over an attached garage in any zone on a single-family lot; one ADU per owner-occupied single-family dwelling. Not allowed in any multi-family dwelling or on a multi-family lot. Separately, Utah Code 10-21-303 makes an internal ADU (one created within the footprint of the house) a permitted use in any area zoned primarily for residential use.

Detached-structure ADUs must be 300 to 1,200 sq ft with no more than 2 bedrooms. Basement ADUs may occupy the entire basement regardless of area or bedroom count. The size subsection states no explicit cap for other attached types (addition or over-garage). The Planning Commission can approve ADUs over 1,200 sq ft by conditional use permit with mitigating conditions. The same section's general accessory-building rules (one story, 14 ft to the wall plate and 20 ft overall, and on lots of half an acre or less a floor area no more than 50% of the house footprint) may also limit a detached ADU structure; the code does not say expressly whether they apply to ADUs, though A.7.e allows a second-story ADU only where the structure meets the zone's height and setback standards for the house.

The owner must occupy either a portion of the main dwelling or the detached accessory unit on the same lot; owner occupied means full-time residency by the owner shown on Davis County tax rolls. Exception for a bona fide temporary absence of 3 years or less (job assignment, sabbatical, or voluntary service) when the owner lived there before leaving and intends to return. State law allows this: 10-21-304(4)(c) lets a city require the owner to live in the house or the detached unit.

The city code requires at least 1 off-street space for the ADU above what the single-family dwelling requires, one more space for ADUs with 2 or more bedrooms, and bars ADU parking in tandem with the main dwelling's required parking; ADUs within 1/4 mile of a bus rapid transit route may reduce the main dwelling's requirement by 1 space, and spaces must be paved and outside street-facing setbacks except in an approved driveway. State law caps what the city may demand: for a detached ADU, 10-21-304(3) (in force October 1, 2026) bars requiring "more than one on-site parking space assigned to a detached accessory dwelling unit that is smaller than 650 square feet" (two for 650 sq ft or larger), and for an internal ADU, 10-21-303(3)(c) allows only one additional on-site space. A 2-bedroom ADU under 650 sq ft, or a 2-bedroom basement unit, therefore faces a city requirement the state does not allow, and 10-20-618(4)(b) bars refusing to count an unobstructed tandem space toward a minimum. The city had not amended this rule as of October 20, 2026; confirm with the community development department.

ADUs (new or existing unpermitted) require a land use permit from the community development department, a staff-level review of the application, site plan, floor plans, and life-safety items, plus a building permit for construction or remodeling; the city page says there is no fee for the land use permit. A Planning Commission conditional use permit is only needed to modify the size, parking, or setback standards. This matches 10-21-304(3)(a), which bars requiring a conditional use permit for a detached ADU in a primarily residential zone.

The ADU may not be sold or detached by deed and shall only be rented. Occupancy is limited to one person, a related family, or up to 4 unrelated persons living as a single housekeeping unit (plus temporary guests under 30 days). Under the short term rental rules, a property with a valid ADU land use permit may rent one of its dwelling units as an STR for up to 365 nights per year, subject to the city's STR land use permit and business license requirements; the owner must live on the property as a primary residence. State law would let the city bar rentals under 30 days (internal ADUs) or 90 days (detached ADUs), but the city has not done so.