The City’s LDO defines an ADU as “a dwelling unit that exists either as part of a principal dwelling or as an accessory building and is secondary and incidental to the use of the property as single-family residential.”

ADUs may be attached to a primary structure or detached and located elsewhere on a property. Check out the American Association of Retired Persons (AARP) summary of ADUs, including their possible forms. (Graphic below is from AARP.)

ADUs help provide a range of housing options. They allow aging in place for family and friends and can also generate income for property owners. They are a form of gentle density, imperceptible in most instances, and allow neighborhoods to absorb incremental infill development.

ADUs are classified as accessory uses within the City’s LDO and are permitted with standards in all of the City’s residential zoning districts, as well as some mixed use and commercial zoning districts. This Permitted Use Table shows the districts where ADUs are permitted.

The standards for ADUs are located within the City’s LDO, sections 30-8-11.2 and 30-8-1-11.2. Now, ADUs are also subject to the requirements of principal uses in a particular zoning district. Those standards differ based on the type and intensity of each zoning district. Standards include setbacks, height, and building coverage of the site.

The location of an ADU on a property may depend on the zoning district setbacks and where the primary dwelling is located on the property, particularly for front building setbacks. However, ADUs are now permitted to adhere to the setbacks for accessory structures, as found in Section 30-8-11.1. 

Previously, an ADU was required to be at least 400 square feet in area. That standard was revised, and there is no longer a minimum dwelling size. As a maximum, an ADU may not be more than 50 percent of the floor area of the primary dwelling. Homeowners should also consider the maximum square footage permitted for all accessory buildings, and overall building coverage of a lot. So, if there are detached garages, sheds or other accessory buildings, their square footage will need to be considered when planning for an ADU.