ADU Rulebook

City · Arizona

ADU rules in Phoenix

4 sources

These are the primary sources for accessory dwelling unit regulations in Phoenix: the city's own zoning code, planning department pages, and permit guides. Start here before talking to anyone: the rules below are what your permit reviewer will apply.

Rules at a glance

Detached (backyard) ADU
Allowed

An ADU may be attached or detached. Two ADUs are permitted per lot with no more than one single-family detached primary dwelling (a third if one ADU is affordable and the net lot is at least 43,560 sq ft). A detached ADU may sit in required rear/side yards with 3 ft interior side/rear and 5 ft street-side setbacks; max 15 ft height in required yards without a use permit.

Zoning Ordinance §§ 608.E.2.a, 706.A.2, 706.A.4
Attached or internal ADU
Allowed

Maximum of one attached ADU per lot; it must comply with the height and setback rules of the primary dwelling and be integrated into its design so the home does not read as a duplex (separate entry allowed).

Zoning Ordinance §§ 706.A.2.a, 706.A.3.a, 706.A.6
Maximum size
75% of the primary dwelling's gross floor area, and no more than 1,000 sq ft on lots up to 10,000 sq ft net; on lots over 10,000 sq ft net, the lesser of 3,000 sq ft or 10% of net lot area

A garage, attached shade structure, or attached carport built as part of a detached ADU does not count toward the ADU's gross floor area. Lot coverage limits of the zoning district still apply.

Zoning Ordinance §§ 706.A.7, 706.A.8
Owner occupancy
Not required

No owner-occupancy requirement appears in the ADU provisions (ZO 608.E.2 and 706.A). State law also bars Phoenix from requiring a familial, marital, employment, or other preexisting relationship between the owner or occupant of the primary dwelling and the ADU occupant.

Zoning Ordinance §§ 608.E.2, 706.A (no requirement stated); A.R.S. 9-461.18(B)(2)
Extra parking
No additional parking for an ADU; the Section 702 parking table requires 2 spaces per primary dwelling unit only

Section 702's residential parking standards attach to the primary dwelling unit and list no ADU line item. A.R.S. 9-461.18(B)(3) prohibits Phoenix from requiring additional parking (or in-lieu fees) to accommodate an ADU.

Zoning Ordinance § 702, Parking Standards table (Dwelling Unit, Single-Family Detached); A.R.S. 9-461.18(B)(3)
Approval process
Permitted use

The Residential Districts Land Use Matrix (608.D) lists ADU as 'pc2' (permitted subject to condition 608.E.2, no use permit) in every residential district column. A Section 307 use permit is needed only for exceptions: a detached ADU taller than 15 ft within required rear/side yards, or one placed between the primary dwelling and the front property line. Standard building permits via the Shape Phoenix portal still apply.

Zoning Ordinance §§ 608.C.3, 608.D (matrix), 608.E.2; 706.A.4.c, 706.A.5
Rental restrictions
None ADU-specific in the Zoning Ordinance; state law protects renting the ADU and the primary dwelling separately as long-term rentals (lease of 90+ days or month-to-month)

Sections 608.E.2 and 706.A impose no minimum lease term and no ADU-specific short-term rental rule. A.R.S. 9-461.18(B)(1) forbids Phoenix from prohibiting separate long-term rental of either unit. Phoenix's citywide vacation rental registration rules (outside the ADU sections) would govern any short-term rental use; not reviewed here.

Zoning Ordinance §§ 608.E.2, 706.A (silent); A.R.S. 9-461.18(B)(1), (I)(3)
The fine print: 7 caveats that can change the picture
  • ADUs are allowed only on lots with no more than one single-family detached primary dwelling; lots with multi-family dwelling units get no ADUs (ZO 608.E.2.a).
  • Two ADUs per qualifying lot; a third requires at least one ADU to qualify as affordable housing and a net lot of at least 43,560 sq ft (ZO 608.E.2.a).
  • Maximum one attached ADU per lot; one detached ADU may be connected to the house by a porch, breezeway, carport, or similar (ZO 706.A.2).
  • Detached ADU height is capped at 15 ft when located within required rear or side yards; taller needs a Section 307 use permit; outside required yards the district height applies (ZO 706.A.4.c).
  • A detached ADU may not sit between the primary dwelling and the front property line without a use permit (ZO 706.A.5).
  • District lot coverage and front setback requirements still apply to any ADU (ZO 706.A.4.b(4), 706.A.7).
  • A.R.S. 9-461.18 does not apply to tribal land or parcels near military airports or high-noise (65+ dB) public airports (subsection G); airport overlay parcels in Phoenix may face different rules.

Summarized from Phoenix's ordinance text, read July 2026; every row links the code section it came from. Rules often vary by zone and lot, so treat this as orientation, not a permit determination, and confirm with the planning department before you commit to a design.

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ADU regulations

Arizona statewide law also applies

Arizona sets baseline ADU rights at the state level. Where local rules are stricter than state law allows, state law usually wins, so both are worth reading.

See Arizona statewide rules

Spotted something outdated?

Zoning codes change. If a link is dead or Phoenix has updated its ordinance, report it and we'll verify against the official source.

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