ADU Rules in Tucson, Arizona
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ADU Rules in Tucson, Arizona
Tucson is home to the University of Arizona and has significant demand for diverse housing options. The city permits ADUs under the Tucson Unified Development Code (UDC). Arizona HB 2720 (2024), codified at ARS § 9-461.18, requires Arizona municipalities with populations over 75,000 — including Tucson — to permit at least one attached, detached, or internal ADU on any lot where a single-family dwelling is allowed.
Permitted ADU Types
- Detached ADU: A standalone structure on the lot
- Attached ADU: Connected addition with separate entrance and kitchen
- Garage Conversion: Converting existing garage to dwelling unit
- Casita: The Southwest term for a small detached guest house — commonly used for ADUs in Tucson
Size Limits
| ADU Type | Maximum Size |
|---|---|
| Detached ADU | 1,000 sq ft |
| Attached ADU | 1,000 sq ft or 50% of primary dwelling |
| Garage Conversion | Existing footprint |
Setbacks
- Front: Must comply with base zone (typically 20 ft in R-1)
- Side: 5 feet minimum
- Rear: 5 feet minimum
- From primary dwelling: No required separation in most zones
Height
- Detached ADU: Maximum 14–18 feet depending on zone
- Cannot exceed height of primary dwelling
Greywater and Water Harvesting
Tucson has strong water conservation ordinances:
- Greywater reuse systems may be permitted and encouraged
- Water harvesting (rainwater collection) encouraged
- Desert landscaping (xeriscaping) required — water-intensive turf is limited
Permit Process
- Check UDC zoning: Verify at Tucson's development portal
- Design plans: Meet UDC setback, height, and design standards
- Submit application: Apply through PDSD permit portal
- Review: Zoning and building code review
- Permit issuance: Receive building permit
- Inspections: All required phases
- Certificate of Occupancy: Required before occupancy
Contact
Tucson Planning & Development Services Department (PDSD) 201 N. Stone Ave, Tucson, AZ 85701 Phone: (520) 791-5550 Website: tucsonaz.gov/pdsd
Disclaimer: Verify current requirements with the Tucson PDSD before starting any project.
More about Tucson Zoning
Sources
- Tucson Unified Development Code — Accessory Dwelling Units·tucsonaz.gov·Accessed 2026-04-07·Direct link
- City of Tucson Planning & Development Services·tucsonaz.gov·Accessed 2026-04-07·Direct link
FAQ
Are ADUs legal in Tucson, Arizona?
Yes. Tucson permits accessory dwelling units in single-family and multi-family residential zones. Arizona HB 2720 (2024) / ARS § 9-461.18 requires municipalities over 75,000 — including Tucson — to permit at least one attached, detached, or internal ADU on any lot where a single-family dwelling is allowed.
What is the maximum ADU size in Tucson?
In Tucson, detached ADUs are limited to 1,000 square feet. Attached ADUs are limited to 50% of the primary dwelling's floor area or 1,000 square feet, whichever is less.
Does Tucson require owner occupancy for an ADU?
Tucson does not require owner occupancy for ADUs under current regulations, consistent with Arizona state law which limits such requirements.
Disclaimer: The information on this website is provided for general informational purposes only and does not constitute legal, financial, or professional advice. Always verify current requirements with your local planning department.