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 2026-06-29 · 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 (480-644-4276 / 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
- Req
Contractor Licensure Verification Form
Required prior to permit issuance
- Req
Fully Dimensioned Site Plan
Showing all property lines, new and existing structures with setbacks, total lot and building square footage
- Req
Architectural, Structural, and Engineer-Sealed Drawings
Complete construction plans; if using a preapproved plan, use as-is (modifications require new submittal) with the Preapproved Housing Design Plan Agreement
- Opt
Preapproved Housing Design Plan Agreement
Required if using a plan from Mesa's Standard Plan Library; must be completed by both parties and submitted to Permit Services
Fee schedule
| Fee type | Amount | Notes |
|---|---|---|
| ADU / casita building permit — Residential Rate Table (valuation-based) | $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 | 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. |
Review timeline
10–10 business days
Mesa’s published plan-review target
Inspection process
- 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
Final inspection
Final inspection when all work is complete; certificate is automatically generated upon permit completion.
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
- Does Mesa have preapproved ADU plans?
- 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 2026-06-29.
- City of Mesa Development Services Department — Permit Services — official building department
- Preapproved Housing Design Plan Program | City of Mesa
- Residential Construction | City of Mesa Development Services
- Development Services Schedule of Fees and Charges (Dec 2025) — PDF
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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