Accessory Dwelling Units (ADUs)
An Accessory Dwelling Unit (ADU) is a secondary dwelling unit that provides living, sleeping, eating, cooking, and sanitation facilities on the same lot as a primary residence. It can be attached to or integrated with the primary residence or built separately as a detached structure in the backyard.
Frequently Asked Questions
Is a recreational vehicle (RV) or mobile home considered an ADU?
Manufactured homes, recreational vehicles (RV), and trailers cannot be used as an ADU. This includes “Tiny Homes” built on chassis with wheels.
How does an ADU differ from a standard home addition?
The ADU has everything you need for independent living: a bathroom, bedroom, kitchen, and a separate entrance from the main house. Expansions of a bedroom or living room don’t offer all the facilities for independent living.
Where are ADUs allowed in Mesa?
ADUs are permitted on any lot where a single-family home is allowed. They are permitted on lots zoned Agricultural (AG), Single Residence (RS), Small Lot Single Residence (RSL), Multiple Residence (RM), Downtown Residence (DR), Mixed Use (MX), Neighborhood Commercial (NC), Limited Commercial (LC), and General Commercial (GC).
How many ADUs can I have on my property?
Any property with a single-family home is permitted to have one attached and one detached ADU. An additional detached ADU is permitted on lots that are over an acre in size if at least one ADU on the property is a restricted-affordable dwelling unit.
What is a restricted-affordable dwelling unit?
A restricted-affordable dwelling unit is one that will be rented or sold to households earning up to 80% of the area median income, as stipulated by a deed restriction or development agreement with Mesa.
How large can my ADU be?
1,000 square feet or 75% of the gross floor area of the primary dwelling unit, whichever is less.
What are the required setbacks for ADUs?
An ADU must be set back at least five (5) feet from the side and rear property lines. The front and street side setbacks must comply with the requirements for the underlying zoning district.
How close can my detached ADU be to my main house?
A detached ADU must be located at least six (6) feet from the primary residence.
How tall can my ADU be?
The height of an ADU must comply with the primary residence height requirements for the underlying zoning district (e.g., RS-6). For details on the maximum allowable height in different zoning districts, please refer to the Mesa Zoning Ordinance.
I have a single-story house. Can I build a two-story detached ADU in the backyard?
Yes. The height of ADUs is regulated by the maximum height allowed for single-family homes in your zoning district.
Is additional parking required for an ADU?
No. Additional parking is not required for an ADU; however, each single residence lot must provide at least two (2) parking spaces.
Do I need a building permit to build an ADU?
Yes, a building permit will be required. The plan set should include a site plan, code data sheet with scope of work, architectural, structural, electrical, plumbing & mechanical plans, specifications, and calculations, as applicable for the proposed work. Learn more about Commercial Construction / Residential Construction
I live in a neighborhood controlled by an HOA. Can I build an ADU on my property?
You will need to check your HOA’s Covenants, Conditions and Restrictions (CC&Rs). HOAs can restrict or regulate ADUs through CC&Rs and these agreements are separate from the City’s zoning regulations.
Can I rent my ADU as a short-term rental (Airbnb, VRBO, etc.)?
Yes. A Short-Term Rental License is required if the unit is rented for 29 days or fewer at a time. Learn more about Short Term Rental Licenses.
Can I sell the ADU separately from the primary residence?
No. The ADU may not be sold separately from the primary residence.
Can my ADU be constructed without utility connections?
No. An ADU must be provided with water, sewer, and electric utilities.
Can my ADU have separate utility meters?
No. An ADU must be served by the same water, sewer, and electric utility provider and meter as the primary residence.
I live in a Historic District. Are there different requirements for ADUs?
No. These requirements apply to all eligible residential properties, including those within a historic district. If your lot is in a Historic District, you will need a Certificate of Appropriateness from the Historic Preservation Office before you can be approved for a building permit. To learn more about the Certificate of Appropriate requirement, please visit Historic Preservation.