Arizona ADU Laws & Permit Guide (2026)
Arizona passed legislation in 2023 preventing cities from prohibiting ADUs on single-family lots. Phoenix, Scottsdale, and Tucson all allow ADUs, with city-level rules governing size, setbacks, and fees.
Arizona ADU At a Glance
Permit Timeline
60–120 days
Average Build Cost
$90,000 – $220,000
Maximum Size
Varies by city (Phoenix: up to 1,000 sq ft)
Owner-Occupancy Required
Varies by city
Impact Fees
Varies by city
Setbacks
Varies; Phoenix requires 6 ft rear and side
Recent Law Changes in Arizona
Prohibited Arizona municipalities from enacting ordinances that ban ADUs outright on single-family lots. Cities may still regulate size, setbacks, and design standards.
Phoenix expanded ADU allowances citywide, permitting detached ADUs up to 1,000 sq ft in all single-family residential zones and streamlining the permitting process.
Find ADU Contractors in Arizona
Browse vetted builders, architects, permit expediters, and ADU lenders serving Arizona homeowners.
Browse Arizona Contractors →Frequently Asked Questions — ADUs in Arizona
Are ADUs legal in Arizona?
Yes. State law (SB 1117, 2023) prevents cities from outright banning ADUs on single-family lots. Major cities including Phoenix, Scottsdale, Tempe, and Tucson all allow ADUs, though each sets its own rules for size, setbacks, and fees.
How much does it cost to build an ADU in Arizona?
Arizona ADU costs typically range from $90,000 to $220,000 for a detached unit, lower than coastal states due to lower labor costs and land costs. Garage conversions and junior ADUs can be significantly less expensive — often $40,000 to $100,000.
What is the maximum size for an ADU in Phoenix?
Phoenix allows detached ADUs up to 1,000 square feet in single-family residential zones. Attached ADUs may not exceed 50% of the primary dwelling's square footage. Other Arizona cities have their own size limits.
Do I need to live on the property to build an ADU in Arizona?
It depends on your city. Phoenix does not require owner-occupancy for ADUs. Scottsdale and some other cities may have owner-occupancy requirements — check with your local planning department.
How long does ADU permitting take in Arizona?
Permit timelines in Arizona vary by city. Phoenix typically processes ADU permits in 60–90 days. Scottsdale and Tucson may take 90–120 days. Simple garage conversions and pre-approved plan sets can be faster.
Sources
- City of Phoenix — ADU Information ↗
- Arizona State Legislature ↗
- City of Tucson — Development Services ↗
Disclaimer: The information on this page is provided for general informational purposes only and does not constitute legal, financial, or construction advice. ADU regulations change frequently — always verify current rules with your local planning department and consult a licensed professional before making decisions. ADUHomeResource.com is not liable for any errors, omissions, or outcomes resulting from use of this information.