Arizona ADU Eligibility Checker

How Arizona ADU Eligibility Works

Arizona's approach to ADUs is entirely city-by-city. The state has declined to adopt a statewide mandate, and no significant bill has advanced in recent sessions. What you can build on your Arizona lot depends on three factors: (1) your city's zoning code and any ADU or 'casita' ordinance, (2) your unincorporated-county rules if you're outside city limits (Maricopa County, Pima County, Coconino County each have their own), and (3) your HOA's CC&Rs. Arizona courts enforce HOA CC&Rs under the Arizona Planned Communities Act, and there is no ADU-specific preemption. The calculator reads Arizona properties as yellow for most configurations because the correct answer is 'check your specific city.'

Phoenix, Tucson, Scottsdale, and Others

Phoenix updated its zoning ordinance in 2023 to allow casitas in most single-family residential districts (R1-6, R1-8, R1-10, R1-14, R1-18 and similar). The permit path is relatively straightforward: submit plans through the Phoenix Development Services, meet setback and height rules, and expect 4–8 weeks of plan review. Tucson has a similarly permissive casita ordinance covering most single-family zones, with a modest conditional-use permit path for non-conforming lots. Scottsdale allows guest houses and casitas in most residential zones but imposes lot-size, setback, and design-review requirements that can rule out smaller lots or require significant redesign. Mesa, Chandler, Gilbert, and Tempe each have their own rules — Tempe is notably permissive, Mesa and Chandler more so than many, Gilbert somewhat stricter on lot-size requirements. Flagstaff allows ADUs in several residential districts with a conditional use permit. Paradise Valley is among the most restrictive Arizona cities for ADUs. Unincorporated Maricopa County allows casitas in RU-43 and RU-43S zones (which cover most unincorporated residential land) with a simple permit.

HOA CC&Rs and Planned Communities

Arizona is heavily HOA-structured, particularly in the Phoenix metro where most post-1980 residential subdivisions are organized as planned communities with active HOAs. The Arizona Planned Communities Act (Title 33, Chapter 16, Arizona Revised Statutes) gives HOAs broad authority to enforce CC&Rs, and courts have consistently upheld CC&R restrictions on accessory dwellings, second residences, and rental activity. There is no statewide preemption analogous to California's. If your HOA's CC&Rs prohibit casitas, accessory dwellings, or rental activity (including short-term rentals), you're blocked unless you can secure a supermajority amendment — typically 67–75% of owners, which is a hard threshold to reach. Check CC&Rs before any design work. A significant share of Phoenix-metro homeowners who start an ADU project discover mid-design that their HOA's CC&Rs block the path.