Phoenix ADU permit requirements
Last reviewed: June 22, 2026
Quick answer
Permitting an accessory dwelling unit (ADU) in Phoenix, Arizona means pulling a building permit from the local authority that issues it. ArchPermit tracks 18 source-cited requirements (12 required, the rest conditional) for this jurisdiction. Submittals go through SHAPE PHX online portal. These requirements were last reviewed June 22, 2026; confirm the exact forms and fees with the local permitting authority.
A source-cited checklist of what an ADU (accessory dwelling unit) permit package needs in City of Phoenix. Every item links to its authoritative source; items that vary are flagged to confirm locally.
Phoenix amended its Zoning Ordinance (text amendment Z-TA-2-24-Y) to comply with Arizona HB2720, now allowing two ADUs per single-family detached lot (a third on lots ≥1 acre where one ADU is deed-restricted affordable). The process is a two-step gate: Site Planning approval must be obtained first, then a residential building-permit plan review. There is no general owner-occupancy requirement. Owner-occupancy only attaches when more than one ADU on a lot is licensed as a short-term rental (handled under STR licensing, not the permit).
- Electrical Plan + Load Calcs / Panel Schedule / One-Linerequired
Separate electrical floor plan; load calculations, panel schedules, and one-line diagram incorporated onto the plan.
source · reviewed 2026-06-22 - Elevations (all four)required
Front, rear, and both side elevations; materials, roof slopes, roofing evaluation-report numbers, and attic ventilation.
source · reviewed 2026-06-22 - Energy Code Compliance (IECC / IRC Ch. 11)required
Prescriptive component compliance, or a simulated-performance energy analysis/compliance report per IECC R405.
source · reviewed 2026-06-22 - Fire-Rating Notes (IRC R301 to R302)required
The ADU process requires noting fire-rating requirements per IRC R301 to R302 on the submittal.
source · reviewed 2026-06-22 - Floor Planrequired
Room uses/sizes, door/window sizes & locations, egress windows, garage/dwelling separation, stairs, and water-heater locations.
source · reviewed 2026-06-22 - Foundation Planrequired
Footing/stem-wall dimensions, anchor bolts, reinforcing, slab details, and soil-class/load-bearing notes per IRC Table R401.4.1.
source · reviewed 2026-06-22 - Framing Plans (roof & floor)required
Size/spacing/span of all framing members; connections from foundation to roof; nailing schedule.
source · reviewed 2026-06-22 - Mechanical Plan + ACCA Manual J/S/D Sizing Calcsrequired
Separate mechanical plan; equipment locations/capacity/fuel; whole-house ventilation; Manual J/S/D load/equipment/duct sizing calcs on the plans.
source · reviewed 2026-06-22 - Plot / Site Planrequired
Property-line dimensions/bearings, existing + proposed construction, setbacks, easements, streets/alleys, allowable vs actual lot coverage, and zoning setback lines/district. Scale no smaller than 1"=20'.
source · reviewed 2026-06-22 - Plumbing Plan (waste & gas isometrics, fixture-unit calcs)required
Waste isometric, gas isometric, pipe materials, low-flow fixture compliance, and water fixture-unit calcs with meter/service sizing.
source · reviewed 2026-06-22 - Residential Construction Permit / Plan Review Applicationrequired
Completed application form (project address, areas, valuation, owner/contractor info, signature).
source · reviewed 2026-06-22 - Site Planning Approval (prior to residential submittal)required
ADUs must have Site Planning approval before residential submittal. This is a gating step confirming the ADU is allowed and legally placed on the lot.
source · reviewed 2026-06-22 - Engineer's / Architect's Sealconditional
Required for unusual structural designs, inadequate shear walls, floor/roof trusses, unusual soils, or electrical service >200A; the PE/architect seals their related sheets.
source · reviewed 2026-06-22 - Grading & Drainage Plan / Permitconditionalverify locally
The ADU process states ADUs do not require a grading & drainage plan, but the G&D guideline lists conditions (hillside, floodplain, lots >0.5 acre, perimeter retaining walls, >2 ft excavation / >1 ft or >100 cu yd fill) that still require a sealed G&D plan; confirm per lot.
source · reviewed 2026-06-22 - Permit-to-Legalize for Unpermitted Structuresconditional
If unpermitted buildings exist on the lot, the applicant must first apply to legalize them before pursuing the ADU permit; ADU rules do not legalize unpermitted structures.
source · reviewed 2026-06-22 - Soil (Geotechnical) Reportconditional
The designer must reference the subdivision soil report and reflect its recommendations (e.g. foundation reinforcing) on the plans where applicable.
source · reviewed 2026-06-22 - Special-Designation Reviews (Hillside / Historic / Floodplain)conditional
Additional reviews if the property is Hillside (slope >1:10), a Historic building/district, or in a Special Flood Hazard Area (an elevation certificate may be required).
source · reviewed 2026-06-22 - Truss Calculations (signed/sealed by AZ PE)conditional
Required when trusses are used: AZ-registered PE signed/sealed truss calcs, treated as a deferred submittal to the inspector.
source · reviewed 2026-06-22
Phoenix ADU permit questions
- Do I need a permit to build an ADU in Phoenix?
- Yes. An accessory dwelling unit (ADU) in Phoenix requires a building permit. ArchPermit tracks 18 cited requirements for this jurisdiction (12 required, the rest conditional). Always confirm the exact forms, fees, and code edition with the local permitting authority that issues the permit.
- What does an ADU permit package require in Phoenix?
- Core required items include: Electrical Plan + Load Calcs / Panel Schedule / One-Line; Elevations (all four); Energy Code Compliance (IECC / IRC Ch. 11); Fire-Rating Notes (IRC R301 to R302); Floor Plan; Foundation Plan, plus 6 more. Each requirement links to its authoritative source, and nothing is permit-ready until an independent licensed professional reviews and seals it.
- How are ADU permits submitted in Phoenix?
- Phoenix accepts permit submittals via SHAPE PHX online portal. ArchPermit prepares a draft package you can submit there after a licensed architect reviews and seals it.