Accessory Dwelling Unit Requirements in Salt Lake City: What Homeowners Need to Know
Adding an accessory dwelling unit can be one of the most practical ways to get more value and flexibility from your Salt Lake City property.
For some homeowners, an ADU becomes a private space for aging parents or adult children. For others, it creates a long-term rental opportunity, a guest suite, or additional living space without leaving a neighborhood they already love.
But before you start sketching a backyard cottage or converting a garage, there is one important reality to understand: an ADU is a residential construction project subject to Salt Lake City's zoning, building, utility, and permitting requirements.
The good news is that Salt Lake City has created a relatively clear framework for ADUs. The key is making sure your specific property, design, and intended use fit within that framework before construction begins.
Here are the major requirements homeowners should understand.
Where Can You Build an Accessory Dwelling Unit in Salt Lake City?
Salt Lake City generally allows ADUs on properties within zoning districts where the use is permitted under the City's zoning code. The City's Planning Division recommends verifying the zoning for the individual property before beginning design work.
That step matters because being located in Salt Lake County does not necessarily mean Salt Lake City zoning rules apply.
Properties in Sandy, Murray, Millcreek, South Jordan, West Jordan, Draper, and other municipalities may be governed by their own zoning ordinances. Even within Salt Lake City, overlay districts and site-specific conditions can affect what can be constructed.
Salt Lake City's current ADU ordinance generally allows one ADU on a property where ADUs are permitted. There is also no minimum lot size specifically required by the City's ADU section.
Before designing anything, confirm:
Your property is actually within Salt Lake City jurisdiction.
The zoning district allows the proposed use.
The property is affected by any overlay district.
Easements or utilities do not interfere with the proposed location.
Existing structures and lot coverage leave enough buildable space.
Salt Lake City's zoning map and Planning Division are valuable starting points for this research.
What Types of Accessory Dwelling Units Are Allowed?
An ADU is a secondary residential unit associated with a primary residence or other qualifying principal use.
Depending on your property and project, this might include:
A basement apartment
A converted portion of the existing home
An attached addition
A converted detached garage
A second-story unit over an accessory structure
A new detached backyard cottage
An internal ADU is located within the principal building, while a detached ADU is constructed separately from the main home.
The distinction is important because detached ADUs are subject to specific requirements for placement, height, setbacks, and maximum floor area.
Salt Lake City also offers several pre-approved detached ADU designs, although every property still requires a site review before a building permit can be issued.
For homeowners beginning their research, Salt Lake City Building Services provides an official ADU resource page with information about planning and pre-approved designs:
Accessory Dwelling Unit Setback Requirements in Salt Lake City
Setbacks are one of the first issues to evaluate when planning a detached ADU.
Under Salt Lake City's current ADU ordinance, a detached ADU generally requires at least:
3 feet from the rear property line
3 feet from an interior side property line
For a corner-side property line, 20% of the lot width or 10 feet, whichever is less
A detached ADU is not permitted in the required front yard. Placement in side, corner-side, and rear yards depends on the location of the main house and compliance with the City's detailed standards.
Existing accessory buildings can create another wrinkle.
If an existing legal garage or other accessory structure is converted into an ADU, the existing setback may sometimes remain. However, an expansion—including adding a second story—must meet applicable ADU setback requirements.
This is one reason Sterling Builders evaluates the property itself before moving too far into design.
A few feet can completely change what is feasible.
How Large Can an Accessory Dwelling Unit Be?
For a detached accessory dwelling unit, Salt Lake City currently limits the ADU to 1,000 square feet of gross floor area.
Internal ADUs do not have the same 1,000-square-foot maximum, provided the overall building remains compliant with the applicable zoning standards.
Homeowners should also consider overall building and yard coverage.
Just because an ADU can be up to 1,000 square feet does not mean every property can accommodate a 1,000-square-foot structure. Existing garages, sheds, patios, additions, the main house, setbacks, easements, and the underlying zoning district can all influence the usable footprint.
A successful ADU design starts by fitting the structure to the property—not forcing a predetermined floor plan onto the lot.
What Are the Height Limits for a Detached Accessory Dwelling Unit?
Salt Lake City's standard maximum building height for a detached ADU is generally 17 feet.
However, the City's code provides options for additional height.
A detached ADU can potentially reach:
Up to 24 feet with a pitched roof
Up to 20 feet with a flat roof
When required side and rear setbacks are increased by one foot for every additional foot of building height above 17 feet, subject to specified exceptions.
A detached ADU located completely within the property's buildable area may also be eligible for the same height allowed for the principal building under the underlying zoning district.
This is where architectural planning becomes particularly important.
If your goal is a two-story ADU, garage apartment, or vaulted interior space, height and setback requirements need to be evaluated together from the beginning.
Does an Accessory Dwelling Unit Require Parking?
Sometimes.
Salt Lake City's ADU ordinance generally calls for one parking stall for the ADU, but several exceptions can eliminate that requirement.
For example, additional ADU parking may not be required when the property:
Is located in a zoning district with no minimum off-street parking requirement
Has qualifying accessible parking above the required minimum
Is within a quarter-mile of a public transit stop
Is within a half-mile of a City-designated bicycle lane or path
The ADU also cannot reduce parking for the principal use below whatever minimum is otherwise required.
For many Salt Lake City properties, particularly those near transit or established bicycle infrastructure, this can provide significantly more flexibility.
But it should be confirmed during planning—not assumed.
Is Owner Occupancy Required?
For a property whose principal use is a single-family dwelling, Salt Lake City's current ordinance generally requires the owner, or a qualifying family member as defined by the code, to reside on the property.
That person can live in either the primary home or the ADU.
The ordinance also contains exceptions, including certain temporary absences and properties whose principal use is a duplex, multifamily dwelling, or qualifying nonresidential use.
If you're building an ADU primarily as a rental investment, this requirement deserves particular attention before construction begins.
The City's FAQ also states that an ADU and primary home cannot simply be subdivided and sold separately under the normal ADU framework.
Can You Use an Accessory Dwelling Unit as an Airbnb?
Generally, not under Salt Lake City's ADU rules.
The City's current code prohibits an ADU from being rented as a short-term rental. The restrictive covenant required for the property must also state that the ADU and principal structure cannot be used for short-term rental purposes.
Salt Lake City's Planning FAQ explains that rental periods of less than 30 days are generally treated as hotel, motel, or bed-and-breakfast uses rather than ordinary residential ADU rentals.
Homeowners planning to generate rental income should therefore approach an ADU primarily as a long-term housing option, not assume it can automatically become a vacation rental.
When a business license is required for renting the unit, the property owner must also satisfy applicable landlord-program requirements before the City's zoning certificate is issued.
What Permits Does an Accessory Dwelling Unit Need?
A building permit is required to establish an ADU in Salt Lake City.
The project also has to comply with applicable building, fire, zoning, and utility requirements.
A typical new detached ADU permit package may require information such as:
A scaled site plan
Property lines
Building dimensions
Setbacks
Easements
Existing and proposed utilities
Floor plans
Building elevations
Foundation and framing details
Electrical plans
Plumbing plans
Mechanical systems
Energy-code documentation
Structural calculations when applicable
Salt Lake City's residential permit checklist specifically requires site and construction information covering setbacks, utilities, structural systems, egress, mechanical, electrical, and plumbing design.
Permit applications are submitted through the City's Citizen Access Portal and go through pre-screening and plan review before approval.
Do You Need a Licensed Contractor to Build an ADU?
In many cases, yes.
Salt Lake City Building Services states that a contractor's license is required for an ADU building permit except in limited circumstances, such as a change of use involving no construction or very small projects that fall within specific state exemptions and do not include mechanical, electrical, or plumbing work.
The City's owner-builder exemption generally cannot be used for ADU construction intended for rental use.
That distinction matters because ADUs typically involve several trades at once.
A detached unit may require excavation, concrete foundations, framing, roofing, insulation, windows, electrical service, plumbing, HVAC, cabinetry, flooring, and exterior work.
Managing each part independently can become complicated quickly.
Does Salt Lake City Require a Restrictive Covenant?
Yes.
Salt Lake City's ADU ordinance requires a restrictive covenant to be recorded against the property with the Salt Lake County Recorder.
Among other information, the covenant documents the primary structure and ADU, their approximate square footage, parking allocation, applicable occupancy restrictions, and the prohibition on short-term rentals.
A copy of the recorded covenant must be provided to the City's Planning Division and attached to the building-permit record before final inspection.
For homeowners who want to read the detailed requirements directly, the City's current ADU ordinance is an excellent second resource:
Historic Districts and Foothill Properties May Have Additional Requirements
Not every Salt Lake City property follows exactly the same path.
The City's ADU rules specifically state that the Historic Preservation Overlay District and Special Foothills Regulations can take precedence where applicable.
That can be particularly important for properties with architectural or site constraints.
Exterior alterations in a locally designated historic district may require Planning approval in addition to standard building permits. Similarly, slopes, soils, utility access, retaining walls, wildfire considerations, and other site conditions can influence the design and permitting process.
This is why two similarly sized lots in Salt Lake City may have very different ADU possibilities.
Building an Accessory Dwelling Unit With Sterling Builders
An ADU may be smaller than a traditional house, but it is still a complete residential construction project.
That means successful planning has to bring zoning, structure, architecture, plumbing, electrical, HVAC, foundations, exterior finishes, and interior function together.
Sterling Builders LLC provides residential construction and home addition services throughout Salt Lake City and surrounding Utah communities. Our team manages complex additions from early planning and structural coordination through permitting, construction, and final finishes.
For an accessory dwelling unit project, that means helping homeowners move from:
“Could an ADU work on my property?”
to a buildable plan that accounts for the realities of the lot.
Whether you're considering a private guest house, a mother-in-law suite, a long-term rental unit, or additional space for family, we approach the project with the same priorities we bring to every Sterling Builders renovation: quality craftsmanship, structural integrity, transparent communication, and a finished space designed to last.
Start Your Salt Lake City ADU With the Right Plan
Building an accessory dwelling unit can create meaningful new possibilities for your home—but the best projects begin long before the first footing is poured.
Start by confirming jurisdiction and zoning. Understand where the unit can sit on the property. Review setbacks, height, parking, utilities, and building coverage. Determine whether historic or site-specific requirements apply. Then develop construction plans that address those requirements before submitting for permits.
Codes and local requirements can also change, so every project should be verified against current Salt Lake City requirements before construction.
Sterling Builders can help simplify that process by coordinating the pieces under one roof—from initial design and planning through construction and final walkthrough.
Thinking about adding an ADU to your Salt Lake City property? Contact Sterling Builders to schedule a consultation and explore what is possible for your home.
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