ADU rules in Phoenix, AZ
Yes. Phoenix requires site planning approval before the residential building submittal.
A single-family lot can have two ADUs, a third on lots of an acre or more with an affordable unit.
Detached ADUs may sit in the rear yard: 3 ft from interior lines, 0 ft from an alley, 15 ft tall.
Rules last checked by a person on October 19, 2026. Guidance only; confirm with Phoenix before you build.
Limits
| ADUs per lot | 2 (a 3rd on lots of 1 acre+ when one is affordable housing) |
|---|---|
| Detached ADU height | 15 ft (a use permit can allow more) |
| Detached ADU setbacks | Street side 5 ft, interior line 3 ft, alley 0 ft; may sit in the required rear yard |
| Rear setback (interior line) | 3 ft (0 ft on a dedicated alley) |
| Attached ADU in rear yard | At least 3 ft from the rear line and 5 ft from a side line, 15 ft tall |
| Size, lots up to 10,000 sq ft | 1,000 sq ft or 75% of the house, whichever is less |
| Size, lots over 10,000 sq ft | 3,000 sq ft, 10% of net lot area, or 75% of the house, whichever is least |
| Short-term rental | Allowed under Arizona law |
Good to know
- An older city process sheet (Jan 2024) says one ADU and no short-term rentals. The newer Beginner's Guide reflects later state law; SetbackIQ follows the newer guide.
- Call 811 at least a few days before you dig footings or post holes. Utility locating is free.
- HOA covenants and deed restrictions can be stricter than city rules. Check yours before you build.
Check your lot
Where to apply
- Phoenix SHAPE PHX permits
- Phoenix Planning & Development
- Phoenix Zoning Ordinance
- Phone: (602) 262-7811
Sources
- Phoenix TRT/DOC/00192, ADU Residential Process (Jan 2024). Checked 2026-10-19.
Must have site planning approval prior to moving on to residential submittal.
- 44 CFR 59.1, definition of development (NFIP). Checked 2026-10-19.
Development means any man-made change to improved or unimproved real estate, including but not limited to buildings or other structures...
- 44 CFR 60.3, floodplain management criteria. Checked 2026-10-19.
Require permits for all proposed construction or other development in the community...
- City of Phoenix, Beginner's Guide to ADUs. Checked 2026-10-19.
Two ADUs are permitted per single-family detached lot... A detached ADU may be located within the required rear yard and may not exceed 15 feet in height... no closer than 5 feet to a street side property line; 3 feet from an interior property line, and 0 f…