Phoenix allows ADUs in residential zones with reasonable size limits and setback requirements. The city's rapid growth has prompted more liberal ADU policies, though regulations remain somewhat conservative compared to western coastal cities.
Zoning & Size Requirements [1][2][3]
Yes, you can build an ADU in Phoenix. A detached ADU can be up to the city's size limit under current Arizona and Phoenix zoning rules.
| Allowed Zones | Single-family residential zones |
| Max Size (Detached) | 1,000 sq ft on lots up to 10,000 sq ft (75% of primary dwelling, whichever is less); on lots over 10,000 sq ft, the lesser of 3,000 sq ft or 10% of net lot area |
| Max Size (Attached) | 75% of primary dwelling, capped at 1,000 sq ft (lots ≤10,000 sq ft) |
| Max Size (JADU) | Not allowed |
| Max Height | 15 ft when within required rear/side yards (greater height may be allowed with use permit) |
| Max Units | 2 per lot (1 attached + 1 detached); a 3rd detached ADU allowed on lots 1+ acre if at least one unit is restricted-affordable |
Setback Requirements [1][2][3]
Phoenix requires a rear setback of about 5 ft for a detached ADU, and no additional parking is required. Owner-occupancy is not required — you can rent it out without living on the property.
| Rear Setback | 5 feet (3 ft for some detached configurations per ZO 706; statute caps rear/side at 5 ft) |
| Side Setback | 5 feet (3 ft for some detached configurations per ZO 706) |
| Front Setback | Per underlying zoning district (no ADU-specific front setback beyond zone standard) — Confirm with Phoenix Planning |
| Parking Required | No additional parking required (ARS 9-461.18 / AZ HB 2720 prohibits ADU-specific parking mandates) |
| Owner Occupancy | Not required for long-term rental; owner must reside on-site only if an ADU built on/after Sept 14, 2024 is used as a short-term/vacation rental |
| Min Lot Size | No ADU-specific minimum; an ADU is allowed on any lot with a permitted single-family dwelling (the smallest single-family district, R1-6, has a 6,000 sq ft minimum lot) |
Permit Process & Fees [4]
An ADU permit in Phoenix typically costs $2,500-$4,200 and takes 60-90 days, through a standard permit review.
| Approval Process | Building permit |
| Review Timeline | 60-90 days |
| Permit Fees | $2,500-$4,200 |
| Impact Fees | $900-$1,600 |
| Plan Check | 2-3 weeks |
| Pre-Approved Plans | Limited availability |
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Construction Costs [5][6]
Building an ADU in Phoenix typically costs $120,000-$240,000 ($135-$270 per sq ft); a garage conversion runs $60,000-$140,000.
| Average Build Cost | $120,000-$240,000 |
| Cost per Sq Ft | $135-$270 |
| Garage Conversion | $60,000-$140,000 |
| Prefab ADU (Installed) | $85,000-$200,000 |
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Rental Income Potential [7][8]
A 2-bedroom ADU in Phoenix rents for around $1,600-$2,200/mo, an estimated 7-10% annual return.
| Avg Rent (1 Bedroom) | $1,250-$1,700/mo |
| Avg Rent (2 Bedroom) | $1,600-$2,200/mo |
| Short-Term Rental | Varies by neighborhood |
| Est. Annual ROI | 7-10% annual return |
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Recent Law Changes
What's Changed Recently
- Arizona HB 2720 (signed May 2024; ARS 9-461.18, effective Jan 1, 2025): cities over 75,000 population must allow at least one attached + one detached ADU by-right on single-family lots, with no owner-occupancy mandate (except STR use), no additional parking, and rear/side setbacks capped at 5 feet
- Phoenix Zoning Ordinance Text Amendment Z-TA-2-24 adopted ADU standards under Section 706 to comply with HB 2720
- Arizona HB 2928 (signed May 2025): extended substantially similar ADU requirements to counties; counties had to adopt compliant standards by Jan 1, 2026 or default provisions apply
- Short-term rentals: HB 2720 allows STR use of ADUs but the owner must reside on the property if an ADU is used as a short-term rental
Tips for Building an ADU in Phoenix
- Phoenix's rapid growth supports strong appreciation potential
- Heat considerations; ensure adequate cooling systems for ADU
- Water availability and HOA restrictions common; verify early
- Strong rental demand due to ongoing population growth
ADU Builders in Phoenix
Looking for an ADU builder in Phoenix? ADU projects need a contractor experienced with local zoning, the permit process, and utility connections — not every general contractor has built one. We match Phoenix homeowners with experienced local ADU contractors who provide free, no-obligation quotes. Getting at least three bids typically saves 20-40% on the same scope.
Sources & References
All data on this page is sourced from official government records and verified market data. View our full methodology.
- ARS 9-461.18 — Accessory dwelling units; regulation; applicability; definitions Government Data — Accessed 2026-06-28
- Phoenix Zoning Ordinance Section 706 — Accessory Uses and Structures (ADU standards) Municipal Code — Accessed 2026-06-28
- Accessory Dwelling Units (ADU) | City of Phoenix Planning Department — Accessed 2026-06-28
- ADU Beginner's Guide | City of Phoenix (PDF) Planning Department — Accessed 2026-02-24
- Angi — ADU Construction Cost Data Market Data — Accessed 2026-02-24
- Angi — Local ADU Contractor Costs Market Data — Accessed 2026-02-24
- Zillow Rental Manager — Market Rent Data Market Data — Accessed 2026-02-24
- HUD Fair Market Rents Government Data — Accessed 2026-02-24
- Phoenix Zoning Ordinance — ADU Amendment Z-TA-2-24 Municipal Code — Accessed 2026-02-24
- Arizona ADU Legislation (SB 1132, 2023) Government Data — Accessed 2026-02-24
Frequently Asked Questions
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