Accessory dwelling units (ADUs), also called second units, granny units, casitas, or cottages, are allowed in all residential zoning districts where single family residences are allowed to promote the goal of affordable housing within the City. The Accessory Dwelling Units Ordinance has the regulations and guidelines for this type of development.


ADUs have many benefits including being:

  • an affordable type of home to construct in California because they do not require paying for land, major new infrastructure, structured parking, or elevators and even impact fees, in some cases.
  • a source of income for homeowners.
  • cost-effective wood frame construction, which is significantly less costly than homes in new multifamily infill buildings.
  • spacious enough to allow as much living space as many newly-built apartments and condominiums, and well-suited for couples, small families, friends, young people, and seniors.
  • a means to allow homeowners the flexibility to share independent living areas with extended family members or caregivers, which additionally allow seniors to age in place when they require more care.

The Cupertino Planning Department will help ensure your project proposal complies with the zoning code and development standards. Feel free to email preliminary plans/queries to  

A building permit is required to build an ADU. Visit the Cupertino Building Permit Center for hours of operation and contact information or email


Technical Assistance Booklet

Information for cities, counties, other local government bodies, and homeowners interested in adding an accessory dwelling unit to their property.

Download the entire booklet(PDF) or select one of the following excerpts:

Please see our Accessory Dwelling Unit Information Sheet and Steps to A Completed ADU Handout for more information on how to plan and build your ADU.

You can contact us to get more choices