At their Sept. 30 meeting, the Scottsdale City Council amended the city’s zoning ordinance related to Accessory Dwelling Units (ADUs) to comply with a state law (HB2928) adopted earlier this year. The new law expands the ability for ADUs to be built on residential lots.  

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. 

Scottsdale opposed this legislation due to its potential impact on neighborhoods and the elimination of local control, but when the bill became law, the city then had to proceed with updating its zoning ordinance via a text amendment (4-TA-2024#2). 

What the law does and does not allow: 

• One attached and one detached ADU per single-family property may be built on residential lots, and a third detached ADU may be built on property one acre or more in size if at least one of the ADUs is an affordable housing unit.  
• Per the state law, Scottsdale’s text amendment restricts the size of multiple ADUs on a single property to reduce impacts to neighborhoods, including potential impacts to water supply and sewer capacity. (State law and the Scottsdale zoning ordinance specify allowable sizes of ADUs in relation to the main dwelling or other units). 
• Cities are restricted from requiring ADUs to have fire sprinkler systems, on-site parking and setbacks of more than 5 feet.  
• Cities are also prohibited from restricting the short or long-term rental of an ADU; Scottsdale requires an ADU owner to live on site if the ADU is used as vacation or short-term rental  
• Homeowner association rules may be more restrictive than the city ordinance. 

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.)   

Failure to amend Scottsdale’s zoning code in accordance with the state law would have allowed ADUs on all residential lots or parcels without limits. 

To date, Scottsdale has received only one formal application for an ADU. 

For more information, visit ScottsdaleAZ.gov and search “ADUs.”