Accessory Dwelling Unit's (ADUs) are attached or detached residential units that are considered an “accessory structure” to a residential unit, and are not counted towards density limitations on a parcel. The intent is to provide affordable housing options for in-laws, live-in caretakers, or rental units. These homes are generally small, and represent an opportunity for addressing the growing housing needs across California. Currently, an ADU can be as small as the 120 square feet requirement of an “efficiency dwelling unit.” However, the California Department of Housing and Community Development (HCD) is changing building code requirements to allow for smaller dwelling units and ADUs.
The 2015 International Building Code (IBC) changes were adopted into the 2016 California Residential Code (CRC), which will take effect on January 1, 2017. The 2016 CRC will allow for habitable rooms smaller than the 120 square feet requirement of the “efficiency dwelling units.” The new requirement for a habitable room is a floor area of not less than 70 square feet. HCD plans to repeal the definition of the “efficiency dwelling unit” and change the dwelling unit requirement for minimum floor area during the 2016 Intervening Code Adoption Cycle with an effective date of July 1, 2018, but does not expect local governing bodies or code enforcement agencies to enforce the provisions of CRC Section R304.5 or CBC Section 1208.4 on single-family homes or “tiny homes” built on a foundation pursuant to the CRC after January 1, 2017.
Detailed information can be accessed in the Information Bulletin.