Yes, but under different rules. Oro Valley, Marana and Sahuarita are under 75,000 residents, so the 2024 state ADU mandate does not bind them; each town's code governs. Unincorporated areas such as the Catalina Foothills fall under Pima County and a separate 2025 state law for counties, A.R.S. § 11-810.01.
How do the places around Tucson compare?
| Place | Who reviews | Status as of October 2026 |
|---|---|---|
| City of Tucson | City PDSD | Covered by HB 2720; code amended October 22, 2024 |
| Oro Valley | Town | Not covered; zoning amended for ADUs, effective January 3, 2025 |
| Marana | Town | Not covered; ADU ordinance adopted, effective at 75,000 residents |
| Sahuarita | Town | Not covered; town code governs |
| Catalina Foothills | Pima County | County ADU law, A.R.S. § 11-810.01 (2025) |
Why aren't the towns covered?
The state law for municipalities, A.R.S. § 9-461.18, applies only to cities and towns with more than 75,000 people. The ASU Morrison Institute lists 16 such cities in Arizona; Tucson is the only one in this part of Pima County. Oro Valley and Marana chose to update their codes anyway, in different ways.
What changes in unincorporated Pima County?
HB 2928 created a parallel law for counties. It largely mirrors the city version: one attached and one detached ADU, at least 75% of the main home or 1,000 sq ft, setbacks capped at 5 feet, no added parking and protected long-term rentals. Two differences matter in the Foothills: a county may require a restricted-affordable unit for the extra ADU on an acre or more, and it may require an adequately sized septic system where there is no sewer.
Pima County drafted an ordinance in 2025 to implement the law. We confirm the adopted version before design. Pima County's separate guest house rules still exist for family-only use.
How do I know which one I am in?
It depends on the parcel, not the envelope: your mailing address may say Tucson even if the parcel is in a town or the county. The county assessor's parcel record and the reviewing office settle it. We check this first in every lot check.
Sources, as of October 2026
- A.R.S. § 9-461.18 and A.R.S. § 11-810.01, as amended and added by HB 2928 (Laws 2025, Ch. 217).
- Town of Marana Ordinance 2024.028.
- Town of Oro Valley code enactments (zoning amendment adopted December 4, 2024).
- Pima County draft Accessory Dwelling Unit Ordinance (2025) and Guest Houses page.
- ASU Morrison Institute, ARCHES fact sheet (September 2025).
Related
Updated October 2026