ADU Rules in Phoenix, AZ (2026)
ADU rules, permit requirements, size limits, and fees for Phoenix, AZ. Source-cited from official municipal code.
Yes, ADUs are allowed in Phoenix, AZ.
Phoenix, AZ permits accessory dwelling units (ADUs) on residential properties. ADUs — also called granny flats, in-law units, backyard cottages, or secondary suites — are secondary housing units on a single-family or multifamily lot. State and local law actively preempts local restrictions, making ADU approval a streamlined ministerial process. In Phoenix, the Phoenix Planning and Development Department (PDD) handles ADU permit applications. Below you will find the current size limits, setbacks, fees, and timeline for building an ADU in Phoenix.
ADU Size Limits
ADU Size Limits in Phoenix: Detached ADU: size varies by zoning — see official source (max height: varies — see official source). Attached ADU: size varies by zoning — see official source.
| Type | Max Size | Max Height |
|---|---|---|
| Detached ADU | See official source | See official source |
| Attached ADU | See official source | See official source |
Permit Fees
ADU Permit Fees in Phoenix: Plan check fee: $250–$1,500. Building permit fee: Based on construction value — typically $800–$3,500. Impact fees: Phoenix impact fees vary — Transportation, Water, and Sewer development fees apply. School fees: None or N/A. Total estimated permit cost: Varies.
| Fee Type | Amount |
|---|---|
| Plan Check | $250–$1,500 |
| Building Permit | Based on construction value — typically $800–$3,500 |
| Impact Fees | Phoenix impact fees vary — Transportation, Water, and Sewer development fees apply |
| School Fees | None |
| Total Estimate | See official source |
Permit Timeline
Phoenix ADU Permit Timeline: Phoenix PDD building permit: typically 3-6 weeks for residential additions. Electronic plan review available via Phoenix ePermits portal. Construction typically 3-9 months. Apply through the Phoenix Planning and Development Department (PDD) online permit portal. Phone: (602) 262-7811.
Setback Requirements
ADU Setback Requirements in Phoenix: Front setback: follows zone standard. Side setback: no minimum. Rear setback: no minimum.
Parking Requirements
Parking Requirements: No additional parking space required for an ADU under Arizona HB 2297. Phoenix cannot require additional off-street parking spaces for an ADU as a condition of approval.
Restrictions & Requirements
- ADU must be on same lot as primary single-family dwelling
- Maximum size: 50% of primary dwelling floor area or 1,200 sqft
- One ADU per single-family residential lot
- ADU must meet Phoenix building code and zoning standards
- Corner lots may have additional setback requirements from street-facing yards
- Impervious surface and lot coverage limits still apply per zone
How Many ADUs Are Allowed?
Number of ADUs Allowed in Phoenix: Single-family lots: 1 ADU per single-family lot. Multifamily properties: ADUs allowed in some multifamily zones per PDD review. Arizona HB 2297 requires at least one ADU to be allowed on lots with single-family dwellings. Phoenix does not currently allow more than one ADU per single-family lot under its local ordinance.
- Single-Family Lots
- 1 ADU per single-family lot
- Multifamily Properties
- ADUs allowed in some multifamily zones per PDD review
Statewide Preemption
ADU Preemption
Arizona state law preempts local ADU rules — local governments cannot impose stricter standards.
View Arizona preemption detailsState Law & Preemption
State Preemption: Arizona House Bill 2297 (HB 2297), effective September 14, 2024, provides partial state preemption of local ADU regulations. The law: removes owner-occupancy requirements; requires municipalities to allow at least one ADU on lots with single-family dwellings; prohibits minimum lot size requirements exceeding 50% of the existing lot; limits rear and side setback requirements to a maximum of 5 feet. Phoenix updated its local ADU ordinance to comply with HB 2297.
Historic District Considerations
Historic District Requirements: Phoenix has 35 historic districts where additional design review may be required for ADU construction. Design review approval is required before obtaining a building permit for properties in historic overlay zones. Phoenix Historic Preservation Office designates historic properties and districts. Locally-designated historic districts include Coronado, Willo, F.Q. Story, Encanto-Palmcroft, Country Club, Windsor Square, Woodlea, and others. Certificate of No Effect or Certificate of Appropriateness required for changes to designated properties. Phoenix has approximately 35 locally designated historic neighborhoods. Look up historic district boundaries at: https://www.phoenix.gov/pdd/historic-preservation
Frequently Asked Questions
Can I build an ADU in Phoenix?
Yes. Phoenix, AZ allows accessory dwelling units. On a single-family lot you can build 1 ADU per single-family lot.
How big can an ADU be in Phoenix?
The maximum size for a detached ADU in Phoenix is 50% of primary dwelling floor area or 1,200 sqft, whichever is less square feet.
How long does it take to get an ADU permit in Phoenix?
The typical ADU permit timeline in Phoenix is Phoenix PDD building permit: typically 3-6 weeks for residential additions. Electronic plan review available via Phoenix ePermits portal. Construction typically 3-9 months.. Total estimated permit fees are $2,000–$10,000 total fees including development fees.
Do I need extra parking for an ADU in Phoenix?
Phoenix parking rules for ADUs: No additional parking space required for an ADU under Arizona HB 2297. Phoenix cannot require additional off-street parking spaces for an ADU as a condition of approval.
Do I have to live on-site to have an ADU in Phoenix?
Owner-occupancy requirement in Phoenix: No owner-occupancy requirement under Arizona HB 2297. Phoenix removed its previous owner-occupancy requirement from its local ADU ordinance in 2024 to comply with state law.
Source: Phoenix Zoning Ordinance Section 606 — Accessory Dwelling Units; Arizona HB 2297 (Laws 2024, Chapter 204). Last verified April 5, 2026. View source