Everything homeowners ask about building an ADU in Scottsdale — answered with 2026 data.
Yes, ADUs are allowed in Very limited residential zones in Scottsdale, AZ. The maximum size for a detached ADU is 1,000 sq ft or 75% of primary dwelling (whichever is less); 500 sq ft for second/third ADU. Attached ADUs can be up to 1,000 sq ft or 75% of primary dwelling (whichever is less). Scottsdale has an ADU-friendliness score of 5/10. Check our full Scottsdale ADU rules page for complete zoning details.
ADU construction in Scottsdale typically costs $140,000-$280,000. The cost per square foot averages $200-$400. Garage conversions are more affordable at $75,000-$170,000, while prefab ADUs cost $110,000-$240,000. Permit fees add $5,000-$8,000 to your budget. See our detailed Scottsdale ADU cost guide.
Detached ADUs in Scottsdale can be up to 1,000 sq ft or 75% of primary dwelling (whichever is less); 500 sq ft for second/third ADU. Attached ADUs are limited to 1,000 sq ft or 75% of primary dwelling (whichever is less). Junior ADUs (JADUs) have a cap of Not allowed. Maximum height is Per underlying zoning district (no ADU-specific height limit beyond zone standard). You are allowed up to 2 per lot (1 attached + 1 detached); a 3rd detached affordable ADU allowed on lots 1+ acre on a qualifying lot.
Rear setback: 5 feet (detached ADU may be as close as 5 ft to rear lot line). Side setback: 5 feet (detached ADU may be as close as 5 ft to side lot line; may not be in required front yard). Front setback: Per zone (detached ADU may not be built in a required front yard). Note that garage conversions may be exempt from setback requirements if the existing structure is already within the setback area.
No additional parking required for the ADU (existing parking for the main dwelling must be maintained; ARS 9-461.18 / HB 2720). Many cities and states have been relaxing ADU parking requirements in recent years. In California, no additional parking is required for ADUs near transit.
Not required for long-term rental; owner must reside on-site only if the main home or ADU is used as a vacation/short-term rental. 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 Scottsdale is typically 120-180 days. Plan check: 6-8 weeks. Pre-approved plans availability: Not available.
Average ADU rental income in Scottsdale: 1-bedroom units rent for $1,500-$2,000/month, 2-bedroom units for $1,900-$2,600/month. Short-term rentals: Not permitted. Expected ROI: 4-6% annual return.
The minimum lot size for an ADU in Scottsdale is None - ARS 9-461.18 bars ADU lot-size restrictions stricter than the zone's single-family standards. 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 Scottsdale, a garage conversion typically costs $75,000-$170,000. The key advantages are lower cost (no foundation work), potential setback exemptions, and faster permitting. Read our complete garage conversion guide.