Arizona ADU Laws & Permit Guide (2026)
Arizona now requires ADUs to be allowed by right statewide: HB 2720 (2024) covers cities with 75,000+ residents, and HB 2928 (2025) extended nearly identical rules to counties, effective January 1, 2026. Local governments can't ban ADUs outright, push setbacks past 5 ft, or demand the ADU match the main house's exterior.
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Arizona ADU At a Glance
Permit Timeline
60–120 days
Average Build Cost
$90,000 – $220,000
Maximum Size
1,000 sq ft or 75% of the primary dwelling, whichever is less, under the statewide baseline (some cities allow more)
Owner-Occupancy Required
Varies by city
Impact Fees
Varies by city
Setbacks
Capped at 5 ft rear/side under HB 2720/2928 in qualifying cities and counties
Recent Law Changes in Arizona
Signed May 23, 2025. Extends the HB 2720 framework to Arizona counties: at least one attached and one detached ADU must be allowed by right on any lot zoned for a single-family home, with an extra detached unit permitted on parcels of one acre or more if it's income-restricted. Counties had until January 1, 2026 to adopt compliant regulations — those that missed the deadline must permit ADUs on all residential lots without limits.
Signed May 21, 2024, effective January 1, 2025. Requires Arizona cities with 75,000+ residents to allow at least one attached and one detached ADU by right on single-family lots, caps rear/side setbacks at 5 ft, bars design-matching mandates, and prohibits restrictions on renting the ADU separately from the main house.
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.
ADU Financial Returns in Arizona
💰 Rental Income Potential
ADU rental income in Arizona varies by location, size, and market conditions. Research comparable rentals in your area to estimate realistic monthly income.
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Use our free calculator to analyze your ADU investment potential. Input your Arizona project costs and estimated rental income.
Arizona ADU ROI Calculator →📈 Investment Considerations for Arizona
Factors That Increase ADU Value:
- • Separate entrance and utilities
- • Proximity to transit and job centers
- • Two bedrooms vs. studio layout
- • Dedicated parking space
- • Private outdoor area
Arizona-Specific Advantages:
- • Growing ADU acceptance
- • Estimated construction cost: $90,000 – $220,000
- • Typical timeline: 60–120 days
- • Max ADU size: 1,000 sq ft or 75% of the primary dwelling, whichever is less, under the statewide baseline (some cities allow more)
Find ADU Contractors in Arizona
Vetted builders, architects, permit expediters, and ADU lenders serving Arizona homeowners.
Frequently Asked Questions — ADUs in Arizona
Are ADUs legal in Arizona?
Yes, statewide. HB 2720 (2024) requires cities with 75,000+ residents to allow ADUs by right, and HB 2928 (2025) extended the same requirement to counties as of January 1, 2026. Phoenix, Scottsdale, Tempe, Tucson, and most Arizona counties now allow ADUs by right, though each still sets its own size, setback, and fee details within the state's limits.
Does Arizona's ADU law apply to unincorporated county land?
Yes, as of January 1, 2026. HB 2928 required Arizona counties to adopt compliant ADU regulations by that date. Counties that missed the deadline must permit ADUs on all residentially zoned parcels without restriction — so unincorporated land may now have fewer limits than some cities.
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 Arizona?
Under the statewide baseline set by HB 2720 and HB 2928, ADUs are generally capped at 1,000 sq ft or 75% of the primary dwelling's square footage, whichever is less. Individual cities can allow larger units — Phoenix allows detached ADUs up to 1,000 sq ft in single-family zones.
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 ↗
- AZ HB 2720 (2024) — LegiScan ↗
- AZ HB 2928 (2025) — BillTrack50 ↗
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.