Accessory Dwelling Units (ADUs)

The Scottsdale City Council adopted Ordinance 4687 on Sept. 30, 2025 to comply with a state law (HB2928) adopted earlier this year. The ordinance allows accessory dwelling units (ADUs) and establishes requirements for ADUs in the city.

ADUs are smaller, self-contained dwelling units built on the same lot as a main single-family residence. While they are similar to guest houses, ADUs differ in that they must contain their own kitchen and sanitary facilities and may be rented out separately from the main house.

The requirements outline specific qualifications, property development standards, and application requirements to construct an ADU on a single-family residential property in Scottsdale.

Three types of ADUs are permitted in Scottsdale: Attached ADU, Detached ADU, and Restricted-Affordable Detached ADU. Each type of ADU has specific requirements.

To construct an ADU on a property in Scottsdale, the property owner must meet the following:

Qualifications

• The ADU can only be located on a single-family residential lot and the lot must have an existing main single-family residential dwelling
• The property owner must provide separately metered electrical and gas utility connections to the ADU. Water and sewer connections will utilize the existing tap at the public water or sewer line, but will then branch on private property to separate connections to the ADU
• The ADU cannot be sold separately from the main single-family residential dwelling on the same lot and a lot may not be subdivided to exclusively accommodate an ADU
• The property owner must reside on the premise for any ADU that is rented, leased, offered for rent or lease, or occupied as a Vacation Rental or Short-term Rental

Property Development Standards

• One attached and one detached ADU per single-family property may be built on residential lots
• A third detached ADU may be built on a property that is one acre or more in size if at least one of the ADUs is an affordable housing unit. There are specific requirements to qualify a unit as affordable
• The first ADU constructed on a property is limited to a size of 1,000 square feet or 75% of the size of the existing main single-family residential dwelling on the same lot, whichever is less
• The second and third (if applicable) ADU constructed on a lot is limited to a size of 500 square feet
• No more than six (6) adults in cumulative total may occupy the main single-family residential dwelling and any ADUs constructed on the same lot
• Building height maximum is that of the underlying zoning district
• Building setbacks for an Attached ADU are the same of the underlying zoning district
• A Detached ADU or Restricted-Affordable Detached ADU may not be constructed in a required front yard or side yard, including the required front yard on the longer street frontage of a corner lot
• A Detached ADU or Restricted-Affordable Detached ADU that is constructed in the rear yard, as defined by the Zoning Ordinance, may be constructed as close as five (5) feet to a side or rear yard
• The minimum distance between an ADU and the main single-family residential dwelling or another ADU on the lot is ten (10) feet
• Private outdoor living space must be provided for each ADU – minimum of five (5) feet deep and fifty (50) square feet in area
• Parking for the main single-family residential dwelling on the property shall be maintained at all times
• Each ADU is required a separate exterior entrance from that of the main single-family residential dwelling on the same lot or another ADU on the same lot
• A path of ingress and egress travel from any ADU to the main street frontage of lot shall be provided
• Each ADU shall provide a unique address and display that address in a prominent location near the entrance to the ADU

While previous legislation (HB2720) passed in 2024 restricted building ADUs within the operating vicinity of airports, the new law reduced the size of those restriction areas and thus expanded areas in Scottsdale where ADUs can be built. (Portions of Scottsdale are within the operating vicinity of both Phoenix Sky Harbor International Airport and Scottsdale Airport.)

The process to receive a permit to construct an ADU is a multi-step process as outlined below:

1. Pre-Application 
   The application process begins with the online submittal of a Pre-Application request. To assist with the Pre-Application process, an applicant is encouraged to submit any information available regarding the proposed ADU, including a site plan, building elevations, and any utility information.
   
2. Pre-Application Meeting 
   After the Pre-Application request is submitted, city staff will schedule a Pre-Application meeting to allow the applicant to discuss requirements for the proposed ADU with city staff.
3. Formal Submittal of Administrative Application 
   After the Pre-Application process, the applicant will be provided direction on how to make a formal application for administrative review of the proposed ADU. Staff may request additional information be provided to assist with review of the formal application.
4. Permit Review 
   After the applicant has submitted a formal application for review and received administrative approval of the formal application, then the property owner or designee can submit construction documents and plans for the proposed ADU for permit review. A permit can then be issued after all applicable code requirements have been reviewed and met.

The Scottsdale Zoning Ordinance makes a land use distinction between a Guest House and an Accessory Dwelling Unit (ADU). While both types of land uses are generally permitted in most residential zoning districts, there are important requirements that are specific to each type of land use.

• Zoning Ordinance:  Sec. 7.900. Accessory Dwelling Units.
  
• Zoning Ordinance:  Sec. 7.203. Vacation rentals or Short-term rentals.
  
• Definitions – Accessory Dwelling Unit, Accessory Dwelling Unit (Attached), Accessory Dwelling Unit (Detached), Accessory Dwelling Unit (Restricted-Affordable Detached), Building, Dwelling