State ADU law
Arizona ADU laws: two ADUs in cities over 75,000
Arizona’s 2024 law (HB 2720) covers cities and towns over 75,000 people.
What to do next: use this research to check your own lot and bids, then tell us about your project. Matching is not live yet, so we reply with information, not a quote.
Get ADU optionsWritten by HyreADU Research Desk Primary-source statute research
The short answer
Arizona ADU laws require cities and towns with more than 75,000 people to allow one attached and one detached accessory dwelling unit on any lot where a single-family home is allowed. A.R.S. § 9-461.18 sets the size allowance at 75% of the house’s floor area or 1,000 square feet, whichever is less.
Cities may not require extra parking, matching design, or rear and side setbacks over five feet.
They may not bar renting the house or the ADU long-term, and they cannot require a fire sprinkler or commercial building code. A city that missed the January 1, 2025 deadline to adopt rules must allow ADUs on residential lots without limits (subsection F).
What Arizona law requires of cities
Each row is from A.R.S. § 9-461.18 as published by the Arizona Legislature.
| Question | What the Arizona statute says | Citation |
|---|---|---|
| How many ADUs? | At least one attached and one detached, as a permitted use. A third detached ADU on lots of one acre or more if one unit is rented as restricted-affordable. | A.R.S. § 9-461.18(A)(1)–(2) |
| Size? | Up to 75% of the house’s gross floor area or 1,000 square feet, whichever is less. | A.R.S. § 9-461.18(A)(3) |
| Long-term rental? | A city may not bar renting the house or the ADU separately as long-term rental housing (a lease of 90 days or more, or month to month). | A.R.S. § 9-461.18(B)(1), (I)(3) |
| Occupant relationship? | A city may not require a family, marital, employment or other relationship between owner and ADU occupant. | A.R.S. § 9-461.18(B)(2) |
| Parking? | No extra parking and no fee in lieu. | A.R.S. § 9-461.18(B)(3) |
| Setbacks and design? | No matching design rule. Height, setback, lot and frontage rules no stricter than for houses. Rear and side setbacks may not exceed five feet. | A.R.S. § 9-461.18(B)(4)–(6) |
| Building code? | A city may not require a commercial building code or a fire sprinkler. | A.R.S. § 9-461.18(D) |
| Utility easements? | No ADU on a public utility easement without written consent of the utilities. | A.R.S. § 9-461.18(E) |
Arizona ADU rules set by state law, as read on the official statute page on October 27, 2026.
Who the law covers and when it took effect
The section applies to cities and towns with more than 75,000 people (subsection H). It does not apply on tribal land, near military airports, or near public airports in areas over 65 decibels (subsection G).
Covered cities had until January 1, 2025 to adopt rules. If a city failed to, ADUs “shall be allowed on all lots or parcels zoned for residential use in the municipality without limits” (subsection F).
What is still up to your city or county
The statute does not mention owner-occupancy, so read your city’s code on that point. Smaller cities and towns, and unincorporated county land, are outside this section.
Building, fire and health codes still apply, apart from the sprinkler and commercial-code limits. Private restrictive covenants still bind, though a city cannot make a permit depend on one (subsection C).
How to check your own city
Answer these in order, in writing, before you pay for drawings.
- 1 Confirm your city’s population
The section covers cities and towns over 75,000. Smaller places set their own rules.
- 2 Check the airport and military overlays
Lots near military or noisy public airports are excluded.
- 3 Find utility easements on your plat
An ADU on an easement needs written utility consent.
- 4 Ask for the city’s ADU ordinance and adoption date
If none was adopted by January 1, 2025, subsection F applies.
What this page does not cover
This page covers the Arizona statute only. It does not cover building codes, septic and well rules, HOA covenants, flood or wildfire overlays, or your city’s fee schedule. Those can still stop a project the statute allows.
We read the statute on October 27, 2026. Laws change, and courts read them.
If your project depends on one clause, have a land-use attorney or the planning department confirm it for your parcel.
For the national picture, see which states have ADU laws; for what to ask at the counter, see the ADU permit guide.
Questions
Which Arizona cities must allow ADUs?
How many ADUs can I build in Arizona?
Can an Arizona city require parking for an ADU?
Can I rent my ADU in Arizona?
Written and audited by
HyreADU Research Desk
Primary-source research, data analysis and fact checking
We are a research desk, not a builder. We read the permit extract, the statute, the HCD return or the fee schedule ourselves, and publish each figure with its source and retrieval date.
Where a number cannot be traced to a primary source, we leave it out and say what we could not verify. Our store-based claims cover California only.
- CA
- the only state this desk will make store-based claims about
- 5
- jurisdictions with extracted ADU permit evidence
- 735
- CSLB-verified companies in the California store
- 0
- national claims from a one-state store
How this desk works
- Primary sources only. Permit counts come from the city or county that issued the permit. Production counts come from HCD’s Annual Progress Report. Rents come from HUD or the Census. We do not cite an article that cites a source; we download the source and compute the figure ourselves.
- This is a California site. The company store is 734 California firms and one New Mexico firm. Permit evidence exists for five named jurisdictions: Los Angeles, San Francisco, Sacramento, San José and unincorporated Marin. A number from that store is titled to those places, never to the United States.
- A permit is not a completion, and a license is not an ADU grade. California licenses no ADU classification. Being named on an ADU permit is evidence of engagement in that jurisdiction, not of quality, completion, or work anywhere else. Owner-builder permits are excluded from contractor counts.
- Calculation is labeled as calculation. Figures we derive are never presented as something HCD, HUD, the Census or a city published. Terner Center research is cited as Terner’s, never restated as ours.
- We do not design, permit or build ADUs, and we take no payment for placement, ranking or a favorable mention. Pages that look like rankings are not: they publish public-record counts and let the reader decide.
- Nothing here is legal, tax or financial advice. Zoning, underwriting and appraisal practice vary by jurisdiction, lender and appraiser. The useful next step on a specific lot is the planning counter and a licensed professional.
Data as of A.R.S. § 9-461.18 read on azleg.gov, retrieved 2026-10-27.. Authorship on this site is organizational: the analysis belongs to the desk rather than to a named individual, and we do not publish credentials we do not hold. Our editorial policy sets out how we source, date and correct what we publish.
Sources & retrieval dates
- A.R.S. § 9-461.18, Accessory dwelling units; regulation; applicability; definitions , Arizona State Legislature Retrieved October 27, 2026.
Planning an ADU in Arizona?
Tell us about your lot and what you want to build. Matching is not live yet, so this is not a quote. We will send ADU options and the next questions to ask your city.
HyreADU is a publisher. It does not design, permit or build ADUs, and matching with builders is not live yet. This page describes state statutory text as published on the retrieval date.
It is not legal advice. Your city or county applies the rules to your lot, and its planning department is the authority for your parcel.