Considering an Accessory Dwelling unit? Here’s What to Know

(480) 360-6640

Give us a call

Drop us a line

1783 W. University Dr. Suite 138
Tempe, AZ

Get directions

Considering an Accessory Dwelling unit? Here’s What to Know

In September 2023, the City of Phoenix legalized accessory dwelling units (ADUs) for owners of detached, single-family homes, joining many other Arizona communities that allow additional structures on residential properties. These backyard units, which are also referred to as casitas, guest houses and mother-in-law units, can have electricity, full kitchens and baths, providing more space and convenience for homeowners and their families.

So, what do you need to know before you tackle adding an ADU to your property? Keep in mind, it’s very important to comply with local regulations and codes as each municipality has its own set of rules and you’ll want to be sure to be compliant.

Here are 10 key considerations as you explore your options for your new Accessory Dwelling Unit construction project:

  1. Check Local Regulations:
  • Contact the local Planning and Development Department for your community to understand the local zoning regulations and building codes for ADUs.
  • Confirm the size, height, setbacks and other specific requirements for ADUs in your area.
  1. Permitting Process:
  • Obtain the necessary permits before starting construction. This may include a building permit, electrical permit, plumbing permit, and others depending on your project. If you’re working with a contractor like MCS, they can help you with the proper permits.
  1. Design and Planning:
  • Create detailed plans for your ADU. Consider factors such as the layout, plumbing, electrical systems and any additional features. An experienced builder can provide you with insight and recommendations to help you navigate the design process, and potentially save you dollars on your investment through proper planning and layout.
  • Ensure that the design complies with the local regulations and zoning requirements.
  1. Utilities and Services:
  • Connect your ADU to existing utility services. This includes water, sewer, and electricity. Check with local utility providers for specific requirements.
  1. Construction:
  • You can hire a licensed contractor like MCS to handle the entire construction process, have MCS perform certain aspects of your project or handle the project on your own if you have past experience. Regardless, ensure that the construction adheres to the approved plans and local building codes.
  1. Inspections:
  • Schedule and pass inspections at various stages of construction with your local municipality. Inspections typically include foundation, framing, electrical, plumbing, and final inspection.
  1. Occupancy Permit:
  • Once the construction is complete and passes all inspections, obtain an occupancy permit from the local authorities before anyone moves into the ADU.
  1. Landscaping and Exterior Finishing:
  • Complete any landscaping or exterior finishing required by local regulations to ensure that the ADU complies with the overall aesthetic of your other dwelling and the neighborhood overall.
  1. Renting and Zoning Compliance:
  • If you plan to rent out the ADU, ensure that you comply with local regulations regarding rental properties and zoning laws. Phoenix, for example, does not allow short-term rentals of ADUs.
  1. Utilities and Amenities:
  • Set up utilities for the ADU, and consider amenities such as parking spaces, separate entrances and landscaping.

Remember that regulations and procedures may vary, and it’s crucial to consult with local authorities and professionals throughout the process. It’s also recommended to work with experienced architects, contractors, and consultants who are familiar with ADU construction in Phoenix and the surrounding areas to ensure a smooth process and compliance with all regulations. Contact the team of construction experts at MCS to learn more about what it takes to add an ADU and make the most of your property.