Arizona Casita & ADU Builder

Yes, and this changed recently. HB 2720, signed in May 2024, requires every Arizona municipality with 75,000 or more residents to permit accessory dwelling units on single-family residential lots — effective January 1, 2025. HB 2928, signed in May 2025, extended substantially similar requirements to counties, with a January 1, 2026 compliance deadline. Cities and counties still control the details through their own ordinances, so the specifics differ by jurisdiction, but a blanket local ban on ADUs is no longer permitted in the covered areas.

Under HB 2720, a municipality must allow an ADU of at least 650 square feet of living space, and may cap the maximum at 1,000 square feet of gross floor area or 75% of the primary dwelling, whichever is less. So on a 1,200 sq ft primary home, 75% is 900 sq ft and that becomes your ceiling. On a 2,000 sq ft home, the 1,000 sq ft cap governs instead. Your city may be more generous than the floor the statute sets — check the local ordinance.

HB 2720 requires covered municipalities to allow at least one attached and one detached ADU as a permitted use on a single-family lot. A second detached ADU must be allowed if one of the units is a restricted-affordable unit. That is the statutory floor — a specific city may allow more.

HB 2720 caps how far a municipality can push you: the largest setback a covered city may require for an ADU is five feet. Cities can require less. This mattered a great deal in practice, because oversized setback requirements were one of the main tools jurisdictions used to make ADUs infeasible on normal-sized lots.

No. HB 2720 specifically prohibits covered municipalities from requiring that an ADU match the exterior design of the primary dwelling. It also prohibits restrictions on leasing the ADU separately from the main house. Note that this constrains your city — it does not constrain a private HOA, which is a separate question you need to check yourself.

Under HB 2720, a covered municipality cannot prohibit leasing the ADU separately from the primary dwelling. Short-term rental rules are a separate matter and cities do regulate those differently. And again: your HOA CC&Rs are their own layer of restriction that state law does not override here.

Cost depends on size, finish level, site conditions, foundation type, and — often the largest single variable — how far utilities have to run to reach the unit. A casita 20 feet from an existing panel and sewer line and one 200 feet out across a lot are very different projects with the same floor plan. Site work and utility connection routinely surprise people more than the structure does. Send us your lot details and we will scope the whole thing, including the parts that are not us.

The build itself is measured in weeks because it happens off-site rather than in your backyard. The schedule driver is almost always plan review and permitting at your city or county, which varies widely by jurisdiction and current backlog. Once your plans are submitted, we can give you a realistic timeline for the part we control.

What matters to your jurisdiction is whether the structure meets code, is permitted, and is inspected — not what the walls were before. A properly built, permitted, inspected container-based dwelling is a dwelling. That said, some jurisdictions have specific provisions or added scrutiny for container construction, so this is worth confirming with your specific planning department early rather than late.