ADU Permits: Gilbert vs Tempe
How do adu permits rules compare between Gilbert, AZ and Tempe, AZ?
Tempe 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 →Tempe, AZ
Maricopa County
Tempe permits accessory dwelling units by right on lots zoned for single-family use under Arizona Revised Statutes section 9-461.18, enacted by HB 2720 in 2024. Tempe (population approximately 185,000) is well over the 75,000 threshold that triggers the state by-right mandate. Tempe's Zoning and Development Code was amended to comply, allowing at least one attached and one detached ADU per single-family lot. Building permits issue through Tempe Community Development.
View full Tempe rules →Key Facts Comparison
| Fact | Gilbert | Tempe |
|---|---|---|
| State Law | ARS §9-461.18 (HB 2720) | ARS 9-461.18 (HB 2720) |
| City Code | Gilbert LDC Chapter 5 | Tempe ZDC + City Code Ch. 8 |
| Review Type | By right (no Use Permit) | - |
| Max Side/Rear Setback | 5 ft | 5 ft (state cap) |
| Review Time | 10-20 business days | - |
| Units Allowed | - | 1 attached + 1 detached by right |
| Population Threshold | - | Tempe ~185k qualifies (over 75k) |
| Review | - | Tempe Community Development |
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.
Tempe FAQ
Can I build a casita in Tempe by right?
Yes. Under Arizona HB 2720 (ARS 9-461.18), Tempe must allow one attached and one detached ADU by right on any single-family lot. Discretionary use permits and public hearings are preempted. You still need building, electrical, plumbing, and mechanical permits through Tempe Community Development.
How close to my property line can the ADU sit in Tempe?
The state statute caps the side and rear yard setbacks Tempe can impose at no more than 5 feet. Tempe's Zoning and Development Code was updated to comply. Front yard setbacks follow the underlying single-family district standards.
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