Straight answers

Are tiny homes legal in Arizona, and where can you put one?

Yes, though no single Arizona rule says so, because building codes here are adopted locally: state law says a county may adopt and enforce a building code for its zoned unincorporated areas, and each county and city writes its own. The pattern across them is consistent. A tiny home on a permanent foundation is treated as a house and is allowed where a single-family house is allowed, if it meets the code that county has adopted. A tiny home on wheels is treated as a trailer or a recreational vehicle, which most places let you live in only in an RV park or in zones set aside for it. Pima County states both halves outright: tiny houses on permanent foundations are permitted in any zone allowing detached single-family dwellings, and tiny houses on a mobile chassis are considered trailers and limited to seven named zones.

Figures verified against the sources below · October 1, 2026

01 — The longer answer

How Arizona counties treat tiny homes

On a foundation, the county's code decides

Pima County defines a tiny house as a single-family dwelling of at most 400 square feet. Its tiny house page still describes the 2018 residential code appendix, while the county has since adopted the 2024 code with its tiny house appendix, so ask which edition your permit falls under. Cochise County says yes to a tiny home on your property and has adopted the tiny house appendix of the 2024 International Residential Code, with its 2024 codes taking effect on 1 September 2026. Phoenix's 2024 building code includes the same appendix. That appendix is what relaxes ceiling heights, lofts and stairs for a small home. Where a county has not adopted it, a small house still has to meet the ordinary residential code.

On wheels, it is a trailer and not a house

Arizona's statutes draw the line in their definitions. A.R.S. 41-4001 defines a recreational vehicle to include a park trailer of 320 to 400 square feet and a travel trailer, which makes a home on wheels a vehicle before zoning is even considered. Counties then apply that. Yavapai County's answer is that small site-built homes are allowed if they meet code, while tiny houses on wheels do not meet the required codes and are considered recreational vehicles. Maricopa County's zoning ordinance does not let a travel trailer be occupied for living, sleeping or housekeeping outside the temporary permits it provides for. Phoenix requires every occupied recreational vehicle to be located in a recreational vehicle park.

Factory-built: approved by the state, placed by the county

A modular home built in a factory answers to the state for how it is built and to the county for where it sits. A.R.S. 41-4006 has local agencies recognise the state's standards as equal to their own building code, and then keeps local authority where it matters for placement: local codes and ordinances governing zoning, fire zones, building setbacks and site development still apply. So state approval of the unit does not settle whether your lot can take it. Before paying a deposit to any manufacturer, ours included, ask to see the Arizona approval for the exact unit you are buying.

County figures worth checking before you rely on them

Several widely repeated figures are not what the counties themselves publish. Pima County's page gives a maximum of 400 square feet and no minimum. Yavapai County's answer gives no size figure at all. Cochise County's older owner-builder answer set a 296 square foot minimum under the 2018 code, and its current tiny home answer, written for the 2024 code, does not repeat it, so confirm that number with the county. Cave Creek is often listed as having adopted the tiny house appendix, and its current town code adopts the 2024 residential code with six named appendices, none of them the tiny house one. The state statute itself says a county may adopt a building code, not that it must, which is why a statewide yes or no is the wrong shape for this question.

Accessory dwelling units are a separate, statewide rule

Arizona has two statutes on accessory dwelling units, A.R.S. 9-461.18 for cities and towns of more than 75,000 people and A.R.S. 11-810.01 for counties. They decide whether a second home must be allowed on a lot, not whether a home on wheels counts as one. Our Arizona guide summarises both with their sources.

02 — Where to go next

The Arizona state guide Where a tiny home can go in the US The tiny house appendix, explained Building codes, state by state How certification works

03 — Sources

Each figure above links to the authority it came from.

A.R.S. 11-861(A): in any county that has adopted zoning, the board of supervisors may adopt and enforce, for the unincorporated areas of the county so zoned, a building code and other related codes, and may exempt areas zoned rural or unclassified
azleg.gov
Pima County, Permitting Regulation for Tiny Houses: a tiny house is a single family dwelling of maximum 400 square feet; tiny houses built on permanent foundations are permitted in any zones allowing detached single family dwellings; tiny houses on mobile chassis are considered trailers and are only permitted in RH, GR-1, SH, MU, CMH1, CMH2 and IR
pima.gov
Pima County Ordinance 2025-15, Exhibit B: adopts Appendix BB (Tiny Houses) with the 2024 International Residential Code
pima.gov
Cochise County Development Services FAQ: the County has adopted Appendix BB (Tiny Houses) of the 2024 International Residential Code; the 2024 codes and 2023 National Electrical Code take effect September 1, 2026
cochise.az.gov
A.R.S. 41-4001: a recreational vehicle includes a park trailer with a gross trailer area of not less than 320 and not more than 400 square feet when set up, and a travel trailer mounted on wheels designed to provide temporary living quarters
azleg.gov
A.R.S. 41-4006: a local enforcement agency shall recognize the minimum standards of the act as equal to any nationally accepted or locally adopted building code standard; nothing prevents the application of local codes and ordinances governing zoning requirements, fire zones, building setback, maximum area and fire separation requirements, and site development
azleg.gov
Yavapai County Development FAQ: small site-built homes are allowed provided the structure meets all required code; tiny houses on wheels do not meet the required codes and are considered recreational vehicles
yavapaiaz.gov
Maricopa County Zoning Ordinance section 814.1: at no time shall a mobile home or travel trailer be occupied or used for living, sleeping or housekeeping purposes, except under the temporary use permits the ordinance provides
maricopa.gov
City of Phoenix Zoning Ordinance section 701: every occupied recreational vehicle shall be located in a recreational vehicle park
phoenix.municipal.codes
City of Phoenix, 2024 Phoenix Building Construction Code: adopts the 2024 International Residential Code with appendices including Appendix BB, Tiny Houses
phoenix.gov
Town of Cave Creek, Town Code 151.02: adopts the 2024 International Residential Code with Appendices BF, CA, CB, CD, CE and CF; no tiny house appendix is listed
codelibrary.amlegal.com

04 — Related questions

Where can you put a tiny home in the US?What is IRC Appendix Q?Are tiny homes legal in every US state?Can you put a tiny house in your backyard in the US?Can you put a tiny house in your backyard in Washington state?

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