What are the tiny house laws in Arizona?

Arizona allows some tiny homes, but the label alone does not tell you where you can live¹. County building codes cover designated unincorporated areas, with possible exemptions for rural or unclassified areas⁴. Ask your county building office which code and building permit apply to your design⁴.

Arizona's state certification leaves local siting rules in place for manufactured homes⁷. Arizona protects certified units against duplicate inspections of work already inspected under the state program⁷. Local zoning, setbacks, fire separation and onsite utility requirements can still apply⁷. Before you order a home, ask the planning office which category it falls under and where you can place it⁷.

Qualifying park models can serve as accessory dwelling units under Arizona's county rule³. The law covers park models with gross interior areas of 320–400 square feet when prepared for occupancy³. Your location must be “zoned for one dwelling unit per three acres or greater”³. Ask county planning whether your zoning designation qualifies before you treat acreage alone as approval³.

Your park model needs a semi-permanent or permanent foundation with utility connections³. Drainage, floodplain, sewer or septic requirements and other county zoning standards still apply³. Your county can require an installation building permit and inspection³. High-noise or accident-potential zones have a separate exception under Arizona law³. This park-model rule does not give you permission to live in every tiny home on wheels³.

Arizona counties must allow qualifying accessory dwelling units where single-family dwellings are allowed². The county rule allows at least one attached and one detached ADU as permitted uses². Lots of at least 1 acre must also allow an additional detached ADU, subject to a possible restricted-affordable requirement².

A separate Arizona rule covers cities and towns with populations greater than 75,000 that exercise the specified zoning powers⁸. Both laws keep applicable building and safety rules, with exceptions for commercial building-code and fire-sprinkler demands^2,8. Tribal land and specified military-airport and airport-noise areas are excluded^2,8. Ask your local planning office whether your tiny-house proposal qualifies as an ADU under the law that applies^2,8.

Arizona's municipal preapproved-plan law sets no minimum size for every new house⁵. Beginning in July 2026, the law calls for standard single-family plans ranging from 800–2,000 square feet⁵. Cities and towns can instead offer home sizes beginning at their own allowed minimum⁵. You should not read that plan program as a ban on every smaller home⁵.

Your options depend on what your local building and planning offices will approve on your Arizona parcel⁴. Ask which dwelling-size standard and building code apply before you pay for drawings⁴. For a manufactured home, ask separately about siting restrictions and state certification⁷. The Arizona Department of Housing's Plan Review team answers plan-review questions for its program⁹.

You need separate septic approval if your Arizona tiny home needs an onsite wastewater system⁶. The Arizona Department of Environmental Quality gives county offices authority to issue septic permits⁶. Send your application to the county where your property is located¹⁰. For the described general-permit systems, approval of a Notice of Intent to Construct authorizes construction for 2 years⁶.

Your Arizona county can require adequate septic capacity before ADU construction if sewer service is unavailable or insufficient². Ask your county wastewater office to review capacity alongside your housing proposal². For a park model, ask county planning to confirm foundation, utility connections and drainage requirements before you buy³. Ask for a written decision that identifies your proposed housing category and the approvals you need³.