ADU Permits: Mesa vs Peoria
How do adu permits rules compare between Mesa, AZ and Peoria, AZ?
Mesa and Peoria 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 →Peoria, AZ
Maricopa County
Peoria permits accessory dwelling units (often locally called casitas) by-right under Arizona Revised Statutes section 9-461.18, enacted by HB 2720 in 2024 and effective for cities over 75,000 population on or before January 1, 2025. Peoria (population approximately 190,000) is subject to the mandate. The Peoria Zoning Ordinance (PZO) Article 14-2 (Residential Districts) was amended to comply. Single-family lots may have one detached and one attached ADU; lots over one acre may add a third detached unit.
View full Peoria rules →Key Facts Comparison
| Fact | Mesa | Peoria |
|---|---|---|
| State Law | AZ HB 2720 (effective 2025) | - |
| City Code | MZO §11-31-3 (Ord. 5883) | - |
| 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) |
| City Reference | - | Peoria Zoning Ordinance Article 14-2 |
| Units Allowed | - | 1 detached + 1 attached (3 if 1+ acre) |
| Maximum Size | - | 75% of primary or 1,000 sq ft |
| Permit Authority | - | Peoria Development and Engineering |
| 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.
Peoria FAQ
Can I build a casita ADU in Peoria by-right?
Yes. Under Arizona HB 2720 (Ariz. Rev. Stat. 9-461.18), Peoria 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, electrical, and fuel-gas permits through Peoria Development and Engineering are still required.
How big can my Peoria ADU be?
Under ARS 9-461.18, your ADU may not exceed 75% of the gross floor area of the primary dwelling or 1,000 square feet, whichever is less. Setback, height, and lot-coverage standards from Peoria's residential zoning district still apply to the structure itself.
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