ADU Permits: Glendale vs Mesa
How do adu permits rules compare between Glendale, AZ and Mesa, AZ?
Glendale and Mesa have similar restriction levels.
Glendale, AZ
Maricopa County
Glendale permits accessory dwelling units 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. Glendale (population approximately 250,000) is subject to the mandate. Glendale City Council adopted ADU amendments to the Uniform Development Code (Chapter 35) on December 10, 2024. Single-family lots may have one detached and one attached ADU; lots over one acre may add a third.
View full Glendale rules →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 →Key Facts Comparison
| Fact | Glendale | Mesa |
|---|---|---|
| State Mandate | Ariz. Rev. Stat. 9-461.18 (HB 2720) | - |
| City Ordinance Adopted | Dec 10, 2024 (Ch. 35 UDC) | - |
| Units Allowed | 1 detached + 1 attached (3 if 1+ acre) | - |
| Maximum Size | 75% of primary or 1,000 sq ft | - |
| Separate Water Meter | Required (Glendale rule) | - |
| Building Code | 2024 IRC / IFGC as adopted | - |
| 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 |
Highlighted rows indicate differences between cities.
Glendale FAQ
Can I build an ADU in Glendale by-right?
Yes. Under Arizona HB 2720 (Ariz. Rev. Stat. 9-461.18) and Glendale's December 10, 2024 amendments to the Uniform Development Code (Chapter 35), Glendale 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 Glendale Building Safety are still required.
Does my Glendale ADU need a separate water meter?
Yes. Glendale requires all accessory dwelling units to have separate utility meters including a separate city water meter, which requires a new water tap to the city water main in the street or right-of-way. The ADU shares the primary address with a Unit 1 and Unit 2 suffix rather than receiving a new address.
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.
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