ADU Rules in Mesa, AZ (2026)
ADU rules, permit requirements, size limits, and fees for Mesa, AZ. Source-cited from official municipal code.
Yes, ADUs are allowed in Mesa, AZ.
Mesa, AZ permits accessory dwelling units (ADUs) on residential properties. ADUs — also called granny flats, in-law units, backyard cottages, or secondary suites — are secondary housing units on a single-family or multifamily lot. State and local law actively preempts local restrictions, making ADU approval a streamlined ministerial process. In Mesa, the Mesa Development Services — Building Inspection Division handles ADU permit applications. Below you will find the current size limits, setbacks, fees, and timeline for building an ADU in Mesa.
ADU Size Limits
ADU Size Limits in Mesa: Detached ADU: up to 50% of primary dwelling floor area or 1,200 sqft, whichever is less (max height: 24 feet). Attached ADU: 50% of primary dwelling floor area. Arizona does not use California's JADU concept. Mesa Zoning Ordinance limits ADU to 50% of primary dwelling or 1,200 sqft. Mesa's RS-6 lots (6,000 sqft typical) with 1,500-2,000 sqft primary homes can support 750-1,000 sqft ADUs — a practical size for rental income in the Phoenix suburbs.
| Type | Max Size | Max Height |
|---|---|---|
| Detached ADU | 50% of primary dwelling floor area or 1,200 sqft, whichever is less | 24 feet |
| Attached ADU | 50% of primary dwelling floor area | Per zone height limit |
Permit Fees
ADU Permit Fees in Mesa: Plan check fee: $250–$1,400. Building permit fee: Based on construction value — typically $800–$3,500. Impact fees: Mesa water, sewer, and transportation development fees apply — typically $3,000–$7,000. School fees: None or N/A. Total estimated permit cost: $2,000–$9,000 total fees. Mesa development fees include Water Capital Recovery Fee ($1,500–$3,000), Wastewater Development Fee ($1,000–$2,500), and Transportation Development Fee depending on ADU location. Fee schedule: https://www.mesaaz.gov/business/permits/fee-schedule
| Fee Type | Amount |
|---|---|
| Plan Check | $250–$1,400 |
| Building Permit | Based on construction value — typically $800–$3,500 |
| Impact Fees | Mesa water, sewer, and transportation development fees apply — typically $3,000–$7,000 |
| School Fees | None |
| Total Estimate | $2,000–$9,000 total fees |
Permit Timeline
Mesa ADU Permit Timeline: Mesa Building Inspection Division processes ADU permits through Mesa's online portal. Standard ADU: 3-5 weeks plan review. Electronic plan submittals available. Construction typically 3-8 months. Apply through the Mesa Development Services — Building Inspection Division online permit portal. Phone: (480) 644-2365.
Setback Requirements
ADU Setback Requirements in Mesa: Front setback: follows zone standard. Side setback: 5 feet. Rear setback: 5 feet. Per Arizona HB 2297, municipalities cannot require rear or side setbacks greater than 5 feet for ADUs. Mesa Zoning Ordinance was updated to reflect 5-foot maximum. Front setback follows primary dwelling line per zone standard. RS-6 zones typically require 20-25 ft front setbacks.
Parking Requirements
Parking Requirements: No additional off-street parking required for ADUs per Arizona HB 2297. Mesa cannot require additional parking for ADUs.
Restrictions & Requirements
- ADU must be on same lot as primary single-family dwelling
- Maximum size: 50% of primary dwelling or 1,200 sqft per Mesa Zoning Ordinance
- One ADU per single-family lot
- Lot coverage limits apply per zone
- ADU must meet Mesa building code and zoning standards
- Corner lots may have additional setback requirements
How Many ADUs Are Allowed?
Number of ADUs Allowed in Mesa: Single-family lots: 1 ADU per single-family lot per Arizona HB 2297. Multifamily properties: ADUs permitted in RM zones per Mesa Zoning Ordinance — consult Mesa Planning for zone-specific standards. Arizona HB 2297 minimum requires 1 ADU per single-family lot. Mesa's local ordinance may allow additional ADUs in some zones. Mesa's Valley Metro Light Rail corridor has higher-density overlay zones that may allow additional unit types.
Single-Family Lots
1 ADU per single-family lot per Arizona HB 2297
Multifamily Properties
ADUs permitted in RM zones per Mesa Zoning Ordinance — consult Mesa Planning for zone-specific standards
State Law & Preemption
State Preemption: Arizona House Bill 2297 (HB 2297, effective September 14, 2024) provides partial state preemption of local ADU regulations. Mesa updated its Zoning Ordinance Section 11-3-3 to comply. The law removes owner-occupancy requirements, requires at least one ADU per single-family lot, limits setbacks to 5 feet rear/side, and prohibits minimum lot size requirements exceeding 50% of existing lot.
Historic District Considerations
Historic District Requirements: Mesa has 2 historic districts where additional design review may be required for ADU construction. Design review approval is required before obtaining a building permit for properties in historic overlay zones. Mesa has limited formal historic district designations compared to Phoenix or Scottsdale. The Mesa Grande Cultural Park preserves ancient Hohokam ruins. The Glenwood historic neighborhood and a portion of downtown Mesa have local historic overlay status. Mesa grew primarily as a post-WWII suburb — relatively few historic structures compared to older Southwestern cities. Look up historic district boundaries at: https://www.mesaaz.gov/business/planning/historic-preservation
Frequently Asked Questions
Can I build an ADU in Mesa?
Yes. Mesa, AZ allows accessory dwelling units. On a single-family lot you can build 1 ADU per single-family lot per Arizona HB 2297.
How big can an ADU be in Mesa?
The maximum size for a detached ADU in Mesa is 50% of primary dwelling floor area or 1,200 sqft, whichever is less square feet.
How long does it take to get an ADU permit in Mesa?
The typical ADU permit timeline in Mesa is Mesa Building Inspection Division processes ADU permits through Mesa's online portal. Standard ADU: 3-5 weeks plan review. Electronic plan submittals available. Construction typically 3-8 months.. Total estimated permit fees are $2,000–$9,000 total fees.
Do I need extra parking for an ADU in Mesa?
No, Mesa does not require additional parking for ADUs.
Do I have to live on-site to have an ADU in Mesa?
No, owner-occupancy is not required for ADUs in Mesa.
Source: Mesa City Code Chapter 11, Section 11-3-3 — Accessory Dwelling Units; Arizona HB 2297 (Laws 2024). Last verified April 6, 2026. View source