ADU Regulations in Arizona (AZ)
Arizona is rated Easy for ADU construction with an ADU-friendliness score of 86/100 (Very ADU-Friendly). Arizona has a statewide ADU law that sets baseline rules across all municipalities. No owner-occupancy requirement. No additional parking required for ADUs. Arizona passed HB 2720 in 2024 (A.R.S. 9-461.18), requiring municipalities with more than 75,000 residents to allow at least one attached and one detached ADU as a permitted use on any lot where a single-family dwelling is allowed, with compliance required by January 1, 2025. The law caps ADU size at 75% of the primary dwelling's gross floor area or 1,000 sq ft (whichever is less), bars rear/side setbacks over 5 feet and additional parking requirements, and protects long-term rental of ADUs. Smaller municipalities are not covered. Owners must reside on the property to use a newly built ADU as a vacation rental.
Full ADU Regulations Summary for Arizona
| ADUs Allowed | Yes |
| Statewide ADU Law | Yes |
| Maximum ADU Size | 1,000 sq ft |
| Owner Occupancy Required | No |
| Parking Required | No |
| Minimum Setback | 5 ft |
| Permitting Timeline | No statewide deadline; varies by municipality |
| Impact Fees | Not limited by state ADU law; varies by municipality |
| Long-Term Rental Allowed | Yes |
| Short-Term Rental (Airbnb) Allowed | Yes |
| Ease of Building | Easy |
ADU Regulations by City in Arizona
ADU rules can vary by city even within the same state. While Arizona's statewide law sets minimum standards, some cities have additional local provisions. Below are ADU details for 4 cities in Arizona.
Phoenix
ADUs allowed on all single-family lots per state law. Maximum 1,000 sq ft or 50% of primary dwelling. No additional parking required.
Tucson
ADUs allowed by right in all residential zones. Tucson had local ADU provisions before the state law and allows up to 1,000 sq ft.
Scottsdale
ADUs permitted per state law. Scottsdale applies design compatibility standards but cannot deny ADUs outright.
Mesa
ADUs allowed on single-family lots. City updated zoning code in 2024 to comply with state ADU law.
How Arizona Compares to Other States
Below is a comparison of Arizona with five states that have similar ADU-friendliness scores. This comparison helps illustrate where Arizona stands nationally.
| State | Score | Statewide Law | Parking Req? | Owner Occ? | Ease |
|---|---|---|---|---|---|
| Arizona (AZ) | 86 | Yes | No | No | Easy |
| Massachusetts (MA) | 85 | Yes | No | No | Easy |
| Minnesota (MN) | 88 | Yes | No | No | Easy |
| Arkansas (AR) | 83 | Yes | No | No | Easy |
| Colorado (CO) | 83 | Yes | No | No | Easy |
| Connecticut (CT) | 83 | Yes | No | No | Easy |
Frequently Asked Questions About ADUs in Arizona
Can I build an ADU in Arizona?
Yes, ADUs are allowed in Arizona. Arizona has a statewide ADU law that requires local jurisdictions to permit ADUs on residential lots. This means your city cannot outright ban ADUs. The ease of building is rated "Easy" with a friendliness score of 86/100.
Do I need to live on the property to have an ADU in Arizona?
No, Arizona does not require owner occupancy for ADUs. You can rent out both the main house and the ADU, which maximizes rental income potential.
How big can an ADU be in Arizona?
The state maximum ADU size in Arizona is 1,000 square feet. Local jurisdictions may set lower limits. Some cities also limit ADU size to a percentage of the primary dwelling (e.g., 50%).
Do I need extra parking for an ADU in Arizona?
No — Arizona does not require additional parking for ADUs. This is a significant advantage, as parking requirements are often the biggest barrier to ADU construction on smaller lots.
How long does it take to get an ADU permit in Arizona?
The permitting timeline in Arizona is: No statewide deadline; varies by municipality. The statewide law sets maximum review periods that cities must comply with.
Does Arizona have a statewide ADU law?
Yes. State law sets the floor that Arizona cities must meet: ADUs up to 1,000 sq ft, no owner-occupancy mandate, no added parking, with permitting handled as: No statewide deadline; varies by municipality. Cities can be more permissive than the state baseline but generally not stricter.
Check ADU Rules for Your City
Use our ADU regulations lookup tool to find the specific rules for your city in Arizona, or browse all 50 states to compare ADU regulations across the country.