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Accessory Dwelling Unit (ADU) / Casita Permit in Mesa, Arizona

Mesa requires a construction permit for attached additions and detached dwellings (casitas/ADUs). Mesa has adopted a Preapproved Housing Design Plan Program per ARS § 9-461.19 — Class 4 covers ADUs in sizes of 200, 600, or 1,000 sq ft. There is no fee for submitting preapproved housing design plans for review; standard construction permit fees apply at permit issuance. Preapproved plans from Mesa's Standard Plan Library may be used with permission from the plan owner (Preapproved Housing Design Plan Agreement required). Additional plans (plot plan, site plan, grading plan, off-site improvement plans) may be required regardless of whether a preapproved plan is used.

Verified 2026-07-16 · Source

When you need this permit

  • A construction permit is required for all attached additions and detached dwellings (casitas/ADUs)
  • Apply through the DIMES online permit system; all submissions are electronic
  • Required documents: Contractor Licensure Verification Form; fully dimensioned site plan; code data sheet with scope of work; architectural, structural, and engineer-sealed drawings; electrical, plumbing, and mechanical plans
  • Contact Planning Division (480-644-4726 / Planning.Info@mesaaz.gov) to determine zoning, setbacks, lot coverage, and architectural design requirements before applying
  • For preapproved housing design plans: complete the Preapproved Housing Design Plan Agreement (signed by both applicant and plan owner) and submit to Permit Services
  • Preapproved ADU plans available for 200 sq ft, 600 sq ft, or 1,000 sq ft units (Class 4 under the Preapproved Housing Design Plan Program)

Required documents

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Fee schedule

ADU / casita building permit — Residential Rate Table (valuation-based)Mesa Development Services Schedule of Fees and Charges (Dec 2025), Residential Rate Table. ADU/casitas are permitted as residential construction. Preapproved plan review: no fee for initial and up to two re-submittals; $120/hour (minimum 1 hour) for additional reviews beyond the third submittal.
$0–$8,333: $220; $8,334–$16,667: $330; $16,668–$24,999: $440; $25,000–$200,000: $500 plus $6/each $1,000 over $25,000; $200,000.01–$500,000: $1,550 plus $9/each $1,000 over $200,000

Review timeline

Plan reviewMesa’s published plan-review target
10–10 business days

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

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

Inspection process

  1. 1

    Inspections at each stage prior to cover

    All required inspections must be conducted at each stage before concealment. Schedule via DIMES, text, or phone. Inspection hours: 6:30 AM – 5:00 PM, Monday–Friday.

  2. 2

    Final inspection

    Final inspection when all work is complete; certificate is automatically generated upon permit completion.

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

Tips

  • Mesa's Preapproved Housing Design Plan Program offers free plan review for ADU designs of 200, 600, or 1,000 sq ft — these preapproved plans can speed up the permitting process.
  • Contact the Planning Division BEFORE applying for a permit to verify zoning, setbacks, lot coverage, and architectural design requirements for your lot.
  • If using a preapproved plan, it must be used as-is — modifications require a new submittal. The Preapproved Housing Design Plan Agreement must be signed by both parties.
  • Even with a preapproved plan, a site plan, grading plan, and off-site improvement plans may still be required — confirm requirements with Permit Services before applying.
  • Mesa refers to ADUs as 'casitas' or 'detached dwellings' in its residential construction documentation.

Frequently asked questions

Mesa requires an accessory dwelling unit (adu) / casita permit for: A construction permit is required for all attached additions and detached dwellings (casitas/ADUs); Apply through the DIMES online permit system; all submissions are electronic; Required documents: Contractor Licensure Verification Form; fully dimensioned site plan; code data sheet with scope of work; architectural, structural, and engineer-sealed drawings; electrical, plumbing, and mechanical plans; Contact Planning Division (480-644-4726 / Planning.Info@mesaaz.gov) to determine zoning, setbacks, lot coverage, and architectural design requirements before applying; For preapproved housing design plans: complete the Preapproved Housing Design Plan Agreement (signed by both applicant and plan owner) and submit to Permit Services; Preapproved ADU plans available for 200 sq ft, 600 sq ft, or 1,000 sq ft units (Class 4 under the Preapproved Housing Design Plan Program). If your project isn't listed, confirm with City of Mesa Development Services Department — Permit Services at 480-644-4273 before starting work.

In Mesa, the published ADU / casita building permit — Residential Rate Table (valuation-based) is: $0–$8,333: $220; $8,334–$16,667: $330; $16,668–$24,999: $440; $25,000–$200,000: $500 plus $6/each $1,000 over $25,000; $200,000.01–$500,000: $1,550 plus $9/each $1,000 over $200,000. These are the jurisdiction's own published figures — see the fee schedule table and source citations on this page.

Mesa's published plan-review target for an accessory dwelling unit (adu) / casita permit is 10–10 business days.

You'll need: Contractor Licensure Verification Form; Fully Dimensioned Site Plan; Architectural, Structural, and Engineer-Sealed Drawings. Depending on your project, Mesa may also ask for: Preapproved Housing Design Plan Agreement. See the required-documents checklist on this page for details on each.

Mesa requires 2 inspection(s) for an accessory dwelling unit (adu) / casita permit, in order: Inspections at each stage prior to cover, Final inspection. Schedule each through City of Mesa Development Services Department — Permit Services (480-644-4273).

Apply through City of Mesa Development Services Department — Permit Services at 55 N. Center St., Mesa, AZ 85201. Phone: 480-644-4273, email: PermitServices@mesaaz.gov. Office hours: Monday–Thursday 7:00 AM – 6:00 PM; Friday (Essential Services Call Center only) 8:00 AM – 12:00 PM. Official information: https://www.mesaaz.gov/Business-Development/Development-Services/Building-Permit-Plan-Review.

Mesa, Arizona has adopted: 2024 International Building Code (IBC) — adopted by Mesa City Council; effective January 8, 2026 (applies to permit applications submitted on or after that date); local amendments published in Mesa City Code Title 4 — Building Regulations (Municode); 2024 International Residential Code (IRC) — effective January 8, 2026; Mesa City Code Title 4 local amendments; existing 2018 IRC standard plans valid for 6 months after adoption; 2024 International Fire Code (IFC) — effective January 8, 2026; Mesa City Code Title 4 local amendments; 2024 International Plumbing Code (IPC) — effective January 8, 2026; Mesa City Code Title 4 local amendments; 2024 International Mechanical Code (IMC) — effective January 8, 2026; Mesa City Code Title 4 local amendments; 2024 International Fuel Gas Code (IFGC) — effective January 8, 2026; Mesa City Code Title 4 local amendments; 2024 International Energy Conservation Code (IECC) — effective January 8, 2026; Mesa City Code Title 4 local amendments; 2024 International Existing Building Code (IEBC) — effective January 8, 2026; Mesa City Code Title 4 local amendments; 2024 International Swimming Pool and Spa Code (ISPSC) — effective January 8, 2026; Mesa City Code Title 4 local amendments; 2023 National Electrical Code (NEC) — Mesa City Code Title 4 local amendments; 2023 NEC (Electrical) Checklist published by Development Services; ADA 2017 / ICC A117.1 — referenced for accessibility compliance; 2025 NFPA 13 (Sprinklers) and 2025 NFPA 72 (Fire Alarm) — referenced for fire protection systems. Local amendments apply — see the Mesa overview page for the full list.

Yes. Mesa's Preapproved Housing Design Plan Program (per ARS § 9-461.19) offers Class 4 ADU plans in sizes of 200, 600, or 1,000 sq ft. There is no fee to review preapproved plans (for initial and up to two re-submittals). Standard permit fees apply at permit issuance. Plans must be used as-is with a Preapproved Housing Design Plan Agreement signed by both parties. Source: City of Mesa Preapproved Housing Design Plan Program page.

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 Mesa building department before you submit. PermitBase is an independent reference and is not affiliated with any government agency.

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