ADU Permits: Mesa vs Scottsdale
How do adu permits rules compare between Mesa, AZ and Scottsdale, AZ?
Mesa and Scottsdale have similar restriction levels.
Mesa, AZ
Maricopa County
Mesa permits ADUs by right in all single-residence districts under Mesa Zoning Ordinance Title 11, Section 11-31-3, as updated by Ordinances 5883 and 5950 to comply with Arizona HB 2720. Internal, attached, and detached ADUs are allowed. Maximum 75% of the primary residence interior habitable area or 1,000 sq ft, whichever is less. No minimum lot size and no additional parking required.
View full Mesa 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 | Mesa | Scottsdale |
|---|---|---|
| State Law | AZ HB 2720 (effective 2025) | - |
| City Code | MZO §11-31-3 (Ord. 5883) | Scottsdale Zoning Ordinance (amended 2024) |
| Max Size | 75% primary or 1,000 sq ft | - |
| Min Lot Size | None | - |
| Parking | Not required | - |
| ADUs Per Lot | 1 attached + 1 detached by right | - |
| 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.
Mesa FAQ
Do I need a permit for a Mesa ADU?
Yes. All ADUs require building permits through Mesa Development Services. Under HB 2720 and MZO Section 11-31-3, review is ministerial (over-the-counter) without public hearings. Full structural, electrical, mechanical, and plumbing trade permits are required.
How many ADUs can I build on my Mesa lot?
At least one attached and one detached ADU are permitted by right on any lot where a single-family dwelling is permitted, with no minimum lot size. On lots of at least one acre, a third ADU (second detached) is permitted only if deed-restricted as affordable to households at 80% AMI.
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.
Compare other topics
See how Mesa and Scottsdale compare on other ordinance categories.
Want to add a third city?
Use our full comparison tool to compare up to three cities.
Open Comparison Tool