ADU Rules in Salt Lake City, UT (2026)
ADU rules, permit requirements, size limits, and fees for Salt Lake City, UT. Source-cited from official municipal code.
Yes, ADUs are allowed in Salt Lake City, UT.
Salt Lake City, UT permits accessory dwelling units (ADUs) on residential properties. ADUs — also called granny flats, in-law units, backyard cottages, or secondary suites — are secondary housing units on a single-family or multifamily lot. State and local law governs the approval process. In Salt Lake City, the local building department handles ADU permit applications. Below you will find the current size limits, setbacks, fees, and timeline for building an ADU in Salt Lake City.
ADU Size Limits
ADU Size Limits in Salt Lake City: Detached ADU: up to 1000 sq ft (max height: 17 feet). Attached ADU: No maximum gross floor area. Salt Lake City Code Title 21A limits ADUs to 1,000 sqft maximum. Utah does not use the JADU designation from California law. Internal ADUs (attached/within dwelling) are permitted by-right statewide under SB 174. Detached ADUs are also allowed in SLC residential zones with building permit.
Permit Fees
ADU Permit Fees in Salt Lake City: Plan check fee: Varies. Building permit fee: Varies. Impact fees: None. School fees: None or N/A. Total estimated permit cost: Varies.
| Fee Type | Amount |
|---|---|
| Plan Check | $300-$1,500 |
| Building Permit | Based on construction valuation — typically $800-$3,500 |
| Impact Fees | Water/sewer impact fees may apply — Salt Lake City Public Utilities charges connection fees |
| School Fees | None |
| Total Estimate | See official source |
Permit Timeline
Salt Lake City ADU Permit Timeline: Permit timeline has not been confirmed — contact the department for current processing times. Apply through the local building department online permit portal. Contact them through their official website for current contact information.
Setback Requirements
ADU Setback Requirements in Salt Lake City: Front setback: follows zone standard. Side setback: 3 feet. Rear setback: 3 feet.
Parking Requirements
Parking Requirements: One parking stall is required for the ADU, except as indicated below: a. The property is in a zoning district with no minimum off street parking requirement; b. The property already contains at least one accessible stall above the minimum parking requirement for the principal use; c. The property is within a ¼ mile radius of a public transit stop; or d. The property is within ½ mile of a city-designated bicycle lane or path.
Restrictions & Requirements
- ADU must comply with Salt Lake City Code Title 21A setback and lot coverage standards
- ADU cannot be sold separately from principal dwelling
- Short-term rental of ADU requires SLC STR license
- ADU must have permanent foundation
- External ADU design should be architecturally compatible with primary structure
- ADU access must maintain required parking and circulation on lot
How Many ADUs Are Allowed?
Number of ADUs Allowed in Salt Lake City: Single-family lots: not confirmed — see official source. Multifamily properties: not confirmed — see official source.
- Single-Family Lots
- 1 ADU per single-family lot (internal ADU required by state law; detached ADU also allowed in most SLC residential zones)
- Multifamily Properties
- ADUs and additional units permitted in RMF zones per Salt Lake City Code
Statewide Preemption
ADU Preemption
Utah state law preempts local ADU rules — local governments cannot impose stricter standards.
View Utah preemption detailsFrequently Asked Questions
Can I build an ADU in Salt Lake City?
Yes. Salt Lake City, UT allows accessory dwelling units. On a single-family lot you can build 1 ADU per single-family lot (internal ADU required by state law; detached ADU also allowed in most SLC residential zones).
How big can an ADU be in Salt Lake City?
The maximum size for a detached ADU in Salt Lake City is 1,000 square feet.
How long does it take to get an ADU permit in Salt Lake City?
The typical ADU permit timeline in Salt Lake City is Salt Lake City Division of Planning processes ADU permits. Standard ADU permit: 4-8 weeks plan review. Internal ADUs typically faster (ministerial approval per SB 174). Construction typically 3-9 months.. Total estimated permit fees are $1,500-$6,000 total permit fees for typical ADU.
Do I need extra parking for an ADU in Salt Lake City?
Salt Lake City parking rules for ADUs: One parking stall is required for the ADU, except as indicated below: a. The property is in a zoning district with no minimum off street parking requirement; b. The property already contains at least one accessible stall above the minimum parking requirement for the principal use; c. The property is within a ¼ mile radius of a public transit stop; or d. The property is within ½ mile of a city-designated bicycle lane or path.
Do I have to live on-site to have an ADU in Salt Lake City?
Owner-occupancy requirement in Salt Lake City: The owner of the property, as defined in this section, shall reside on the property. For the purposes of this title, "owner occupant" shall mean the following: 1. An individual who is listed on a recorded deed as an owner of the property; 2. Any person who is related by blood, marriage, adoption to an individual who is listed on recorded deed as an owner of the property; or 3. An individual who is a trustor of a family trust who possesses legal ownership of the property. 4. Exceptions: a. Owner occupancy is not required for an ADU located on a property with a principal use as a duplex, multi-family dwelling, or non-residential land use. A single-family dwelling with an attached ADU does not constitute a duplex; b. The owner has a bona fide, temporary absence of 3 years or less for activities such as military service, temporary job assignments, sabbaticals, or voluntary service (indefinite periods of absence from the dwelling shall not qualify for this exception); or c. The owner is placed in a hospital, nursing home, assisted living facility or other similar facility that provides regular medical care, excluding retirement living facilities or communities.
Source: Salt Lake City Code Title 21A; Utah Code Section 10-21-303 (Internal Accessory Dwelling Units; renumbered from §10-9a-530 by SB1008 §121, eff. 11/06/25; legacy citation §10-9a-534 was a mis-citation — that statute is the building-design/parking prohibition, now §10-20-618). Last verified April 5, 2026. View source