Everything homeowners ask about building an ADU in Salt Lake City — answered with 2026 data.
Yes, ADUs are allowed in All residential zones where residential uses permitted in Salt Lake City, UT. The maximum size for a detached ADU is No maximum size; height-limited. Attached ADUs can be up to No maximum size for internal ADUs. Salt Lake City has an ADU-friendliness score of 8/10. Check our full Salt Lake City ADU rules page for complete zoning details.
ADU construction in Salt Lake City typically costs $180,000-$350,000. The cost per square foot averages $300-$350. Garage conversions are more affordable at $120,000-$200,000, while prefab ADUs cost $100,000-$180,000. Permit fees add $2,000-$4,000 estimated to your budget. See our detailed Salt Lake City ADU cost guide.
Detached ADUs in Salt Lake City can be up to No maximum size; height-limited. Attached ADUs are limited to No maximum size for internal ADUs. Junior ADUs (JADUs) have a cap of N/A (Utah uses different classifications). Maximum height is 17 ft maximum (detached); can increase to 24 ft pitched or 20 ft flat with increased setbacks (+1 ft per additional foot over 17 ft). You are allowed up to 1 ADU per lot only on a qualifying lot.
Rear setback: Increase 1 ft for each foot of height above 17 ft. Side setback: Increase 1 ft for each foot of height above 17 ft. Front setback: Comply with base zone. Note that garage conversions may be exempt from setback requirements if the existing structure is already within the setback area.
1 space minimum (in addition to primary dwelling requirement). Many cities and states have been relaxing ADU parking requirements in recent years. In California, no additional parking is required for ADUs near transit.
Required - owner must reside on property (either main or ADU). Note that owner-occupancy rules vary by state law — California and several other states have eliminated this requirement for standard ADUs.
The ADU permit review timeline in Salt Lake City is typically 2-8 weeks for approval; 7-9 weeks for construction after permit issued; 3+ months total typical. The plan check process takes approximately Included in 2-8 week timeline. Pre-approved plans availability: City offers ADU standard plans; ADU Handbook available.
Average ADU rental income in Salt Lake City: 1-bedroom units rent for $1,200-$1,600/month, 2-bedroom units for $1,600-$2,200/month. Short-term rentals: Restricted; long-term preferred. Expected ROI: 8-12 year payback; property value increase 20-35%.
The minimum lot size for an ADU in Salt Lake City is No specific minimum. This applies to detached ADUs — garage conversions and JADUs may have different or no lot size requirements.
Garage conversions are one of the most popular and affordable ADU options. In Salt Lake City, a garage conversion typically costs $120,000-$200,000. The key advantages are lower cost (no foundation work), potential setback exemptions, and faster permitting. Read our complete garage conversion guide.