Accessory Dwelling Unit (ADU) Permit in Gilbert, Arizona
Accessory Dwelling Units in the Town of Gilbert are regulated under Land Development Code Section 5.2.3. Each lot may have one (1) detached ADU and one (1) attached ADU; parcels over one acre may have an additional detached ADU if it is a restricted-affordable unit. ADU must be less than 75% of the primary dwelling's gross square footage. ADUs 1,000 SF and under go directly through Building Permits (OneStopShop); ADUs over 1,000 SF require an Administrative Use Permit through Planning first, then a Building Permit. Applications at onestopshop.gilbertaz.gov.
Verified 2026-06-29 · Source
When you need this permit
- Submit through OneStopShop portal at onestopshop.gilbertaz.gov
- ADU must be less than 75% of the primary dwelling's gross square footage
- ADUs ≤ 1,000 SF: Building Permit only through OneStopShop
- ADUs > 1,000 SF: Administrative Use Permit through Planning first, then a Building Permit
- Each lot limited to one (1) detached ADU and one (1) attached ADU; additional detached ADU allowed on parcels >1 acre if restricted-affordable
- Architectural articulation is required
- Soils report required unless subdivision has one on file or a signed soils report waiver is provided (call 480-503-6700)
- All utility services for ADU must come from the primary structure's utility connections (a private in-line meter is allowed but is not read by the utility company)
- Separate address for ADU may be requested but is not required
- Accessory structures over 200 SF require a Building Permit (but not a Use Permit)
- HOA/CC&R approval may be required in addition to Town permit
Required documents
- Req
Building Permit Application
Submitted through OneStopShop at onestopshop.gilbertaz.gov
- Opt
Administrative Use Permit Application (if ADU > 1,000 SF)
Required from Planning Division before building permit can be issued for ADUs over 1,000 SF
- Req
Architectural Plans
Plans showing architectural articulation, dimensions, setbacks, and relationship to primary dwelling
- Req
Soils Report (or Waiver)
Required unless subdivision has one on file; call (480) 503-6700 to check
- Req
Site Plan
Showing ADU location, setbacks, lot coverage, and relationship to primary structure
Fee schedule
| Fee type | Amount | Notes |
|---|---|---|
| Building Permit Fee — valuation-based | Same valuation-based table as residential construction; $50.00 minimum for work valued $1.00–$1,100.00 | Source: Town of Gilbert Development Services Fee Schedules (doc 5883), Building Permit and Plan Review Fees Table, effective July 1, 2025, Resolution 4563. ADU permit fee calculated from the standard Building Permit Fee valuation-based table. |
| Plan Review Fee | 65% of the calculated Building Permit Fee | Source: Town of Gilbert Development Services Fee Schedules (doc 5883), effective July 1, 2025, Resolution 4563. |
| Administrative Use Permit Fee (if ADU > 1,000 SF) | $1,000 | Source: Town of Gilbert Development Services Fee Schedules (doc 5883), Planning & Development Fees and Charges — Administrative Use Permit, effective July 1, 2025, Resolution 4563. |
| Development Fees | May apply — contact Development Services for current development fee schedule | Per the ADU Guide (doc 50846, February 2025): 'development fees may apply.' System Development Fees for single-unit residential: Parks & Recreation $9,358; Traffic Signals $1,754; Roads $3,010; Police $1,138; Fire $1,447 (per the July 1, 2025 fee schedule, doc 5883, adopted July 1, 2024 per Town Council April 16, 2024). Contact Development Services to confirm whether and what SDFs apply to a specific ADU. |
Review timeline
8–12 business days
Gilbert’s published plan-review target
Inspection process
- 1
Foundation / Slab Inspection
Inspection of foundation and slab before pouring concrete
- 2
Rough Framing / Systems Inspection
Framing, rough plumbing, mechanical, and electrical inspections
- 3
Final Inspection
Final inspection confirming ADU complete and ready for occupancy
Tips
- ADUs ≤ 1,000 SF go directly through Building Permits (no Planning approval needed). ADUs > 1,000 SF need an Administrative Use Permit from Planning first ($1,000 fee).
- The ADU must be less than 75% of the primary dwelling's gross square footage.
- Utility connections: ADU utility services must come from the primary structure's connections. A private in-line meter is allowed but is not read by the utility company.
- Architectural articulation is a required design element — confirm requirements with Development Services.
- A separate address is possible for the ADU but not required.
- Check HOA and CC&R requirements in addition to Town permits — HOA approval may be needed.
- Accessory structures (non-ADU) over 200 SF require a Building Permit (no Use Permit needed).
Frequently asked questions
- How many ADUs can I have on my property in Gilbert?
- Each lot may have one (1) detached ADU and one (1) attached ADU. Parcels over one acre in size may have an additional detached ADU if it is a restricted-affordable unit. See Land Development Code Section 5.2.3.
- Does my ADU need a soils report?
- Yes, unless your subdivision already has one on file with the Town, or you provide a signed soils report waiver. Call (480) 503-6700 to check if your subdivision has one on file.
Sources & verification
Verified against official sources. Last reviewed 2026-06-29.
- Town of Gilbert Development Services Department — Plan Review and Inspection Division — official building department
- Town of Gilbert Accessory Structures and ADU Guide (February 2025)
- Town of Gilbert Development Services Fee Schedule (Resolution 4563, effective July 1, 2025) — archived snapshot; live doc 5883 currently 404s
- Plan Review and Inspection Division Project Review Time Frames (March 2026)
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 Gilbert building department before you submit. PermitBase is an independent reference and is not affiliated with any government agency.
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