Key Facts Full Breakdown Violations FAQ Sources

Pima County, AZ Accessory Structures: Tiny Homes (2026)

Some Restrictions

Tiny home rules in Pima County, AZ — covering tiny houses on wheels (THOWs), park model RVs, and tiny home on foundation builds — determine where they are legal and how they get permitted.

Verified 1 month ago|Source: Pima County Development Services — Building Permits →

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Key Facts

Foundation Required: Yes for permanent dwelling
THOWs: Classified as RVs, not dwellings
Building Code: 2018 IRC adopted
Permits

City-specific rules exist: Marana, Oro Valley, and Sahuarita have their own tiny homes rules that differ from Pima County's county-level regulations. If you live in one of those cities, check the city-specific page instead.

Summary

Pima County permits tiny homes as accessory dwelling units under the 2024 Zoning Code update for unincorporated areas. Tiny homes on wheels are classified as recreational vehicles and cannot serve as permanent dwellings. Site-built or modular tiny homes on foundations must meet IRC building standards and obtain standard building permits through Pima County Development Services.

Full Breakdown

Pima County Development Services regulates tiny homes through the county zoning code and building code (based on 2018 IRC). A tiny home on a permanent foundation is treated as a standard dwelling and must comply with minimum habitable space requirements, setbacks, and utility connections. Tiny homes on wheels (THOWs) are classified as RVs under Arizona law and may not be used as primary residences in residential zones. The county requires a building permit for any structure intended for habitation. Minimum lot sizes in unincorporated Pima County vary by zone (CR-1 requires 36,000 sq ft minimum, CR-3 allows 1-acre lots). Accessory dwelling units including tiny homes must connect to approved water and wastewater systems or obtain ADEQ permits for private wells and septic. Contact Pima County Development Services at 520-724-9000 for permit requirements.

Violations & Fines

Building or occupying a tiny home without permits is a code violation subject to notice of violation and fines. Unpermitted structures may face stop-work orders and mandatory removal. Using a THOW as a permanent residence violates zoning code and may result in daily fines until corrected.

Frequently Asked Questions

Can I live in a tiny home on wheels in Pima County?

No. Tiny homes on wheels are classified as recreational vehicles under Arizona law and cannot be used as permanent residences in residential zones. You must place a tiny home on a permanent foundation and obtain building permits to use it as a dwelling.

Do I need a permit for a tiny home in Pima County?

Yes. Any structure intended for habitation requires a building permit from Pima County Development Services. The home must meet IRC building standards, connect to approved utilities, and comply with zoning setback and lot coverage requirements.

What is the minimum size for a tiny home in unincorporated Pima County?

The county follows IRC standards which require at least one habitable room of 120 sq ft minimum. The home must also meet ceiling height, egress, and ventilation requirements under the adopted building code.

How does Pima County compare?

See how Pima County's tiny homes rules stack up against other locations.

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Pima County, AZ Accessory Structures: Tiny Homes (2026)

Key Facts

Summary

Full Breakdown

Violations & Fines

Frequently Asked Questions

Sources & Official References

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