ADU Permits: Phoenix vs Scottsdale
How do adu permits rules compare between Phoenix, AZ and Scottsdale, AZ?
Scottsdale has fewer restrictions than Phoenix.
Phoenix, AZ
Maricopa County
Phoenix processes ADU permits through Planning and Development under PZC Section 608 (Casita Ordinance) and 2024 Phoenix ADU updates. Arizona HB 2928 (effective 2025) preempts local restrictions in cities over 75,000 residents, requiring ministerial approval for ADUs meeting state standards.
View full Phoenix rules →Scottsdale, AZ
Maricopa County
Scottsdale permits accessory dwelling units by-right under Arizona Revised Statutes Sec. 9-461.18, enacted by HB 2720 in 2024 and effective January 1, 2025 for cities over 75,000 population. Scottsdale (population approximately 241,000) qualifies. The City of Scottsdale Zoning Ordinance was amended to comply. Single-family lots may have one detached and one attached ADU; lots over one acre may add a third detached ADU. Permits are issued through Planning & Development Services.
View full Scottsdale rules →Key Facts Comparison
| Fact | Phoenix | Scottsdale |
|---|---|---|
| State Law | AZ HB 2928 (2025) | - |
| City Code | Phoenix PZC Section 608 | Scottsdale Zoning Ordinance (amended 2024) |
| Max Size | 75% primary or 1,000 sq ft | - |
| Review Type | Ministerial (no hearing) | - |
| Review Time | 10-20 business days | - |
| State Mandate | - | Ariz. Rev. Stat. 9-461.18 (HB 2720) |
| Units Allowed | - | 1 detached + 1 attached (3 if 1+ acre) |
| Permit Authority | - | Scottsdale Planning & Dev Services |
| ESLO Constraints | - | Apply in north Scottsdale |
| By-Right Standard | - | Yes on single-family lots |
Highlighted rows indicate differences between cities.
Phoenix FAQ
Do I need a permit for a Phoenix ADU?
Yes. All ADUs require building permits through Phoenix Planning and Development under PZC Section 608. Under HB 2928, review is ministerial (over-the-counter) without public hearings, but full structural and trade permits are required.
How big can my Phoenix ADU be?
Under Arizona HB 2928, ADUs are limited to 75 percent of the primary dwelling size or 1,000 square feet, whichever is less. Phoenix cannot impose a smaller maximum size than state law.
Scottsdale FAQ
Can I build an ADU in Scottsdale by-right?
Yes. Under Arizona HB 2720 (Ariz. Rev. Stat. Sec. 9-461.18), Scottsdale must allow one detached and one attached ADU by-right on every single-family lot. Lots over one acre may add a third detached unit. Building, plumbing, mechanical, and electrical permits through Planning & Development Services are still required.
Does the Environmentally Sensitive Lands Ordinance affect my ADU?
Yes if your lot is in the ESLO overlay (most of north Scottsdale). HB 2720 does not exempt ADUs from generally applicable slope, native-vegetation salvage, grading, and view-corridor requirements. Detached ADU placement and pad design must still comply with the ESLO.
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