ADU Laws in Arizona (2026)
Arizona state ADU law details, key provisions, preemption status, and recent legislative changes for accessory dwelling units.
Law Name
Arizona House Bill 2297 (HB 2297)
Effective Date
2024-09-14
Preempts Local Ordinances
Yes — state law overrides local restrictions
Has State Law
Yes
Key Provisions
Removes owner-occupancy requirement — property owner does not need to live on the lot to build or rent an ADU
Requires municipalities to allow at least one ADU on residential lots with single-family dwellings
Prohibits minimum lot size requirements for ADUs that exceed 50% of the existing lot size
Limits rear and side setback requirements to a maximum of 5 feet for ADUs
Prohibits municipalities from requiring additional off-street parking spaces for ADUs
Applies to municipalities with populations over 5,000 — covers all major Arizona cities
Partial preemption — cities retain authority over design standards, height limits, and maximum unit size within state-defined bounds
Legislative History
2024 — Arizona HB 2297 (Laws 2024, Chapter 204)
Arizona Governor Katie Hobbs signed HB 2297 into law. The bill provides partial state preemption of local ADU regulations, effective September 14, 2024. Cities with populations over 5,000 must update their local ADU ordinances to comply. Phoenix, Tucson, Mesa, Chandler, Scottsdale, and all major Arizona cities are affected.
2016 — Arizona SB 1350 — Short-Term Rental Preemption
Arizona preempted local governments from prohibiting short-term rentals outright. Later amended by SB 1168 (2022) to restore some local regulatory authority including registration requirements, safety standards, and nuisance enforcement.
Official Sources
What Does Preemption Mean for Local Cities?
Because Arizona law preempts local ordinances, individual cities cannot impose restrictions stricter than the state standard. A city may still have additional administrative requirements, but cannot deny ADU applications that comply with state minimums.
Learn about Arizonazoning preemption →Source: Arizona House Bill 2297 (HB 2297). Last verified April 5, 2026. View source