When did Tucson start allowing casitas?

Tucson's Mayor and Council adopted the original ADU code amendment after an October 19, 2021 public hearing, allowing casitas on residential lots. The 2024 amendment, adopted October 22, 2024, updated it for state law.

Does Tucson require parking for a casita?

No. The 2024 amendment removed minimum parking requirements for ADUs, and state law bars cities over 75,000 residents from requiring added parking or a fee in lieu.

Does Tucson have pre-approved casita plans?

Yes. The Casita Model Plan Library launched in January 2024; the city's 2024 review counted seven pre-approved models, purchased from their designers.

Home / Guides / Tucson casita rules

What are the casita rules in Tucson in 2026?

Updated October 2026

As of October 2026, Tucson allows two ADUs per residential site under its October 22, 2024 code amendment, effective November 21, 2024, with a possible third on lots over an acre if it is rented at affordable rates. Parking minimums are gone. State law also guarantees at least 75% of the main home or 1,000 sq ft, whichever is less.

How did Tucson's rules get here?

2021: after an October 19 public hearing, Mayor and Council allowed one ADU on residential lots, with size tied to lot area, a 12-foot height limit for detached units, one parking space unless waived near transit, and a cool roof on each new ADU.
May 21, 2024: the governor signed HB 2720, setting a floor for cities over 75,000.
October 22, 2024: Tucson adopted amendments that increased the number of ADUs per lot, changed the size calculation, adjusted heights, removed parking minimums and amended setbacks. They took effect November 21, 2024.
May 23, 2025: HB 2928 amended the state law, including the airport-area exemptions.
February 2026: a House committee rejected HB 4028, which would have removed the 1,000 sq ft cap and 5-foot setback limit.

What does state law guarantee in Tucson?

One attached and one detached ADU on a single-family lot, as a permitted use with no public hearing.
At least 75% of the main home's floor area or 1,000 sq ft, whichever is less.
No side or rear setback over 5 feet, and no height rule stricter than for a house in that zone.
No parking requirement, no fee in lieu, no design-matching, no sprinkler mandate.
The right to lease the house and the ADU separately for 90 days or more.
No requirement that you and the tenant be related or connected.

Floor plan and site plan drawings: Architectural blueprints spread out on a surface

What about short-term rentals?

State law lets cities require the owner to live on the property when an ADU built after the law took effect is used as a vacation or short-term rental. We confirm Tucson's current STR requirements before you plan around nightly income.

Which 2021 rules may no longer apply?

The 12-foot height limit, the parking space and the lot-size formula were all changed or overridden in 2024. Whether the cool roof requirement carried over is something we confirm in the current code. Older articles and city pages still quote the 2021 numbers, so check the date on anything you read.

Where does it depend?

On your zone, lot coverage, any Historic Preservation Zone review, utility easements and your HOA. The state floor is a minimum; the rest comes from the parcel.

Sources, as of October 2026

City of Tucson PDSD, Accessory Dwelling Units Code Amendment page and 2021 adoption notice.
City of Tucson PDSD, 2024 Year in Review.
KOLD 13 News, October 25, 2024, on the updated amendment.
A.R.S. §§ 9-461.18 and 9-500.39, as enacted by HB 2720 (2024) and amended by HB 2928 (2025).
Scottsdale Area Association of Realtors, February 26, 2026, on HB 4028.

Which rules apply to your lot?

Send your address. We check Tucson's code and the state floor for your parcel.