ADU Permits: Gilbert vs Surprise
How do adu permits rules compare between Gilbert, AZ and Surprise, AZ?
Surprise has fewer restrictions than Gilbert.
Gilbert, AZ
Maricopa County
Gilbert processes ADU permits through Development Services. Arizona HB 2720 (signed May 2024, effective January 1, 2025) preempts most local ADU restrictions in cities over 75,000 residents and codifies ADU rules at ARS 9-461.18. Gilbert (population over 280,000) must allow at least one attached and one detached ADU per single-family lot by right.
View full Gilbert rules →Surprise, AZ
Maricopa County
Surprise must allow accessory dwelling units (ADUs) by right in single-family residential zones under Arizona HB 2720 (2024), codified at ARS § 9-461.18. With a population near 143,000 the city exceeds the 75,000 threshold and is preempted from prohibiting one attached and one detached ADU per single-family lot. The Surprise Zoning Ordinance Section 106-10.2 (ADUs) within Chapter 106 (Zoning and Use Standards) implements the state mandate, and building permits issue through the Community Development Department.
View full Surprise rules →Key Facts Comparison
| Fact | Gilbert | Surprise |
|---|---|---|
| State Law | ARS §9-461.18 (HB 2720) | - |
| City Code | Gilbert LDC Chapter 5 | - |
| Review Type | By right (no Use Permit) | - |
| Max Side/Rear Setback | 5 ft | - |
| Review Time | 10-20 business days | - |
| Code Section | - | Surprise Zoning § 106-10.2 |
| State Mandate | - | ARS § 9-461.18 (HB 2720) |
| Population Trigger | - | Surprise > 75k (by-right) |
| Permitted Zones | - | RR, R-1, R-2, R-3 (by right) |
| Min Detached Size | - | 1,000 sq ft (state floor) |
Highlighted rows indicate differences between cities.
Gilbert FAQ
Do I need a Use Permit for a Gilbert casita?
No, not since January 1, 2025. ARS 9-461.18 (HB 2720) preempted Gilbert's prior Use Permit requirement. ADUs are now a permitted use by right on single-family lots, though you still need building, electrical, plumbing, and mechanical permits through Development Services.
How many ADUs can I have on my Gilbert lot?
At least one attached and one detached ADU on any single-family lot. Lots one acre or larger qualify for a third detached ADU if one of the units is designated as a restricted-affordable dwelling unit under ARS 9-461.18.
Surprise FAQ
Can I build an ADU in Surprise by right?
Yes. Arizona HB 2720 (ARS § 9-461.18) requires Surprise to permit one attached and one detached ADU per single-family lot by right because the city exceeds 75,000 population. File for a building permit with Surprise Community Development under Zoning § 106-10.2.
Does the Sun City Grand HOA affect my ADU rights?
Yes. ARS § 9-461.18 binds the city but does not override private HOA covenants. Sun City Grand (The Grand), Sun Village, and similar age-restricted communities can restrict or prohibit ADUs through CC&Rs. Read your HOA documents before applying.
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