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–R302)required
The ADU process requires noting fire-rating requirements per IRC R301–302 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 — 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