Building a casita in Phoenix, Arizona

How the state ADU law applies in Phoenix

Phoenix has a population well above 75,000, so it's covered by Arizona's new state ADU statute. That means the city is required to allow, on any single-family lot:

• At least one attached accessory dwelling unit (part of your existing home).
• At least one detached accessory dwelling unit — a true backyard casita.
• A third detached ADU on lots of one acre or more, if one unit is deed-restricted affordable.

The baseline Phoenix must follow

• Size: up to 1,000 sq ft on lots ≤ 10,000 sq ft; the lesser of 3,000 sq ft or 10% of net lot area on larger lots — and never more than 75% of the main home's gross floor area.
• Setbacks: Phoenix cannot require setbacks greater than 5 feet.
• Parking: Phoenix cannot require additional off-street parking beyond what the primary home has.
• Owner-occupancy: Phoenix cannot require you to live in the main house.
• Materials: Phoenix cannot require exterior materials that match the primary dwelling.
• Height / coverage: Phoenix cannot impose stricter height or lot-coverage limits on the ADU than on the primary home.

Phoenix-specific rules

Phoenix regulates ADUs under Zoning Ordinance Section 706. The city publishes a Beginner's Guide to ADUs and a residential ADU process guide — pull both before you meet with a builder.

• Up to two ADUs are permitted alongside a single-family home (a maximum of one may be attached). A third detached ADU is allowed on lots of 1 acre or more if at least one ADU is deed-restricted affordable.
• Under Section 706, a detached ADU may sit as close as 5 feet from a street-side property line and 3 feet from an interior side or rear line.
• Phoenix prohibits using an ADU as a short-term rental. Long-term rental (30+ days) is allowed.

How you actually get a permit in Phoenix

Permits are submitted through the Shape Phoenix online portal or in person at City Hall. You'll need a site plan showing ADU size, location, and utility connections. Typical permitting fees run roughly $1,000–$2,500 (this is a typical range — confirm current fees with the city before you budget).

What a Phoenix casita actually costs

Phoenix metro pricing runs about $150–$300+ per square foot. Most detached builds land between $150,000 and $300,000 all-in. See the full breakdown in our Arizona casita cost guide and pair it with the financing options that fit your situation.

What still varies by city

Even though the state sets the baseline, Phoenix's specific permit process, submittal checklist, plan-review timeline, and impact fees are set locally. Building codes, mechanical requirements, and utility connection rules are also administered by Phoenix and its utility providers. Confirm the details with the Phoenix planning department before you sign anything with a builder.

HOAs still matter in Phoenix

Big chunks of Phoenix sit inside HOA-governed neighborhoods. The state ADU law does not override private HOA covenants (CC&Rs). Read yours before you start. Our HOA rules page walks through exactly what to look for.

Practical steps for Phoenix homeowners

• Pull your CC&Rs and confirm your neighborhood permits detached ADUs (or that you have no HOA).
• Call Phoenix planning and ask for their current ADU submittal checklist under the new state statute.
• Get a survey. Setbacks are 5 feet minimum — no guessing.
• Line up financing before you commission plans. See our financing guide.
• Get at least two contractor bids with itemized scope.

What a casita costs in Phoenix

Costs in Phoenix track the metro Phoenix baseline: roughly $150 to $300+ per square foot, with most detached builds landing between $150,000 and $300,000 all-in. Utility runs, site conditions, HOA design requirements, and contractor overhead drive most of the variance. Read the full Arizona casita cost guide.