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Accessory Dwelling Unit (ADU) Permit in Phoenix, Arizona

An Accessory Dwelling Unit (ADU) — also called a guest house, casita, or granny flat — is a separate, self-contained living area, either fully detached or attached to an existing home, with its own kitchen, bathroom, living area and sleeping quarters. In late 2024 the Phoenix City Council approved ordinance changes to comply with new state ADU laws. Where a lot has no more than one single-family detached primary dwelling, two ADUs are permitted in addition to the primary dwelling (a third may be permitted under certain circumstances). Phoenix offers a free pre-approved ADU Standard Plan Library; a plot/site plan is still required for permitting.

Verified 2026-07-16 · Source

When you need this permit

  • Permitted where a lot has no more than one single-family detached primary dwelling: up to two ADUs in addition to the primary dwelling (a third ADU may be permitted under certain circumstances)
  • Each ADU may be up to 75% of the gross floor area of the main house, not to exceed 1,000 sq ft for lots up to 10,000 sq ft, or 3,000 sq ft for lots over 10,000 sq ft
  • Must comply with the zoning district's lot-coverage guidelines (typical single-family zones include R1-6, R1-10)
  • A plot/site plan is required for permitting (even when using a pre-approved ADU Standard Plan)
  • Pre-approved ADU Standard Plans are free to City of Phoenix residents but must be submitted as-is without modifications (changes require a new submittal)

Required documents

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Fee schedule

ADU building permit — valuation-based (Table A)PDD Fee Schedule, Table A (Ordinance G-7465, effective 1/20/2026). Phoenix does not publish a separate ADU-specific fee; the ADU is permitted as a residential structure under Table A.
Per valuation-based Table A (e.g. a typical ADU valued in the $50,001–$200,000 range = $703 on first $50,000 plus $9 per additional $1,000), plus applicable plan review fee

Review timeline

Plan reviewTypical estimate — confirm current times with the Phoenix building department
~10–30 business days

How long did your Accessory Dwelling Unit (ADU) Permit permit actually take in Phoenix?

Anonymous — one question, no email. Answers are combined and only shown once at least 5 people have reported.

Inspection process

  1. 1

    Pre-pour / footing

    Underground plumbing/electrical, rebar, hold-downs, footing depth/width, and UFER grounding before concrete is poured (for detached ADUs)

  2. 2

    Rough trades / framing

    Rough plumbing, mechanical, and electrical, and framing inspected before insulation and drywall

  3. 3

    Final

    All work complete per approved plans; fixtures, devices, and equipment inspected at final

See the full Phoenix inspection guide — scheduling & re-inspection fees →

Tips

  • Phoenix updated its ADU ordinance in late 2024 to comply with new Arizona state ADU laws — up to two ADUs are now allowed on a typical single-family lot.
  • Each ADU may be up to 75% of the main house's gross floor area (capped at 1,000 sq ft for lots up to 10,000 sq ft, 3,000 sq ft for larger lots).
  • Pre-approved ADU Standard Plans are free but must be used as-is; any modifications require a new submittal.
  • Find your lot size on the Maricopa County Assessor's Office website to estimate lot coverage before designing your ADU.

Frequently asked questions

Phoenix requires an accessory dwelling unit (adu) permit for: Permitted where a lot has no more than one single-family detached primary dwelling: up to two ADUs in addition to the primary dwelling (a third ADU may be permitted under certain circumstances); Each ADU may be up to 75% of the gross floor area of the main house, not to exceed 1,000 sq ft for lots up to 10,000 sq ft, or 3,000 sq ft for lots over 10,000 sq ft; Must comply with the zoning district's lot-coverage guidelines (typical single-family zones include R1-6, R1-10); A plot/site plan is required for permitting (even when using a pre-approved ADU Standard Plan); Pre-approved ADU Standard Plans are free to City of Phoenix residents but must be submitted as-is without modifications (changes require a new submittal). If your project isn't listed, confirm with City of Phoenix Planning & Development Department at 602-262-7811 before starting work.

In Phoenix, the published ADU building permit — valuation-based (Table A) is: Per valuation-based Table A (e.g. a typical ADU valued in the $50,001–$200,000 range = $703 on first $50,000 plus $9 per additional $1,000), plus applicable plan review fee. These are the jurisdiction's own published figures — see the fee schedule table and source citations on this page.

Plan review for an accessory dwelling unit (adu) permit in Phoenix typically runs 10–30 business days. This is an estimate, not a published figure — confirm current review times with City of Phoenix Planning & Development Department at 602-262-7811.

You'll need: Residential Construction Permit / Plan Review Application (TRT/DOC/00030); Plot / Site Plan. Depending on your project, Phoenix may also ask for: ADU Standard Plan (optional). See the required-documents checklist on this page for details on each.

Phoenix requires 3 inspection(s) for an accessory dwelling unit (adu) permit, in order: Pre-pour / footing, Rough trades / framing, Final. Schedule each through City of Phoenix Planning & Development Department (602-262-7811).

Apply through City of Phoenix Planning & Development Department at 200 West Washington Street, 2nd/3rd Floor, Phoenix, AZ 85003. Phone: 602-262-7811, email: pdd@phoenix.gov. Office hours: Mon–Fri 8:00 AM – 5:00 PM (City business hours), except major holidays. Official information: https://www.phoenix.gov/administration/departments/pdd.html.

Phoenix, Arizona has adopted: 2024 Phoenix Building Construction Code (PBCC) — adopted by Phoenix City Council June 18, 2025, effective August 1, 2025 (Ordinance G-7397); 2024 International Building Code (IBC), including Appendix E, with Phoenix amendments (IBC Chapter 1 Administrative Provisions adopted); 2024 International Residential Code (IRC), including Appendices BA, BB, BF, BG, BI, BJ, BO, CA, CB, CD, CE, CF, NB, and NE, with Phoenix amendments; 2024 International Mechanical Code (IMC), with Phoenix amendments; 2024 International Fuel Gas Code (IFGC), with Phoenix amendments; 2024 International Energy Conservation Code (IECC), with Phoenix amendments; 2024 International Existing Building Code (IEBC), with Phoenix amendments; 2024 International Swimming Pool and Spa Code (ISPSC), with Phoenix amendments; 2024 International Plumbing Code (IPC), including Appendices C and E, with Phoenix amendments; 2024 Uniform Plumbing Code (UPC), including Appendices A, B, C, I and M, with Phoenix amendments; 2023 National Electrical Code (NEC), with Phoenix amendments; 2024 International Green Construction Code (IgCC) — optional; 2022 ASME A17.1 Safety Code for Elevators and Escalators; 2023 ASME A17.3; 2022 ASME A17.6; 2023 ASME A18.1; ADA: referenced ICC A117.1-2017 as scoped in the amended 2024 IBC, plus the 2010 ADA Standards for Accessible Design. Local amendments apply — see the Phoenix overview page for the full list.

Where a lot has no more than one single-family detached primary dwelling, Phoenix allows up to two ADUs in addition to the primary dwelling (a third may be permitted under certain circumstances). Each ADU may be up to 75% of the main house's gross floor area, capped at 1,000 sq ft (lots up to 10,000 sq ft) or 3,000 sq ft (larger lots). Source: City of Phoenix Accessory Dwelling Units page, phoenix.gov.

Sources & verification

Verified against official sources. Last reviewed 2026-07-16.

Fees, timelines, and adopted codes are researched from each jurisdiction's published records — see how we verify. Requirements change and vary by project, so always confirm the current details with the Phoenix building department before you submit. PermitBase is an independent reference and is not affiliated with any government agency.

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Accessory Dwelling Unit (ADU) Permit in other cities

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