Pima County, AZ Accessory Structures: ADU Rental Restrictions (2026)
Key Facts
- Governing section
- Pima County Code § 18.09.020.U.9
- Applies to
- Unincorporated Pima County only
- Max ADU size
- 75% of main dwelling or 1,250 sq ft
- Coverage rule
- Counts toward accessory lot coverage limit
Summary
In unincorporated Pima County, the zoning code lets an accessory dwelling unit be rented short-term or long-term, and its square footage still counts toward the lot's coverage limits.
Accessory dwelling unit(s) may be used as a short- or long-term rental.
10. The owner of a vacation rental or short-term rental of thirty days or less must reside on the property if the property contains an accessory dwelling unit.
11. No additional parking is required for accessory dwelling units to accommodate an accessory dwelling unit.
12. All Pima County Code regulations still apply, including, but not
limited to, Protected Peaks ( 18.61), Hillside Development Zone ( 18.61), Historic Preservation ( 18.63), Grading Limits ( 18.61), Native Plant Preservation ( 18.72), Buffer Overlay Zone (
18.67), Pima County Flood Control District requirements, and Scenic Routes.
13. This section does not apply to lots or parcels that are located on tribal land, on land in the territory in the vicinity of a military airport or ancillary military facility as defined in A.R.S. Section 28-8461, on land in the territory in the vicinity of a federal aviation administration commercially licensed airport or a general aviation airport or on land in the territory in the vicinity of a public airport as defined in A.R.S. Section 28-8486 that has a noise level of greater than sixty-five decibels. (Ord. 2025-27 § 2, 2025; Ord. 2025- 8 § 2, 2025; Ord. 2023-19 § 1, 2023; Ord.
Official source re-checked September 7, 2026: no newer edition of the code had been published (publisher’s edition: 2026 S-64: Contains Supplement, with local legislation through Ordinance 2026-9, passed 7-28-2026, current through 7-28-2026).
Full Breakdown
Pima County Code § 18.09.020.U (Accessory Dwelling Units), applicable only in the unincorporated county, not Tucson, Marana, Oro Valley, Sahuarita or South Tucson, states accessory dwelling units 'may be used as a short- or long-term rental.' The ADU's square footage counts toward the parcel's accessory-structure lot coverage limit rather than being exempt, and size is capped at 75% of the main dwelling's floor area or 1,250 square feet, whichever is smaller.
Violations & Fines
Operating outside these standards is a zoning code violation; Pima County can impose civil penalties up to $750 per day for an individual under Code § 18.95.040.
Frequently Asked Questions
Can I rent out my ADU in unincorporated Pima County?
Does this rule apply in Tucson?
Sources & Official References
Other rules in Pima County
Compare Pima County to another location·View the Arizona accessory structures overview
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