What are Accessory Dwelling Units?

Accessory Dwelling Units (ADUs) are known by many names: granny flats, in-law units, backyard cottages, secondary units and more. No matter what you call them, ADUs are an innovative, affordable, effective option for adding much-needed housing in California.

Recent state legislation gives California cities more flexibility and latitude for allowing homeowners to build ADUs. Three separate bills were introduced and signed by Governor Brown during the last session; SB 1069 (Wieckowski), AB 2299 (Bloom), and AB 2406 (Thurmond). Each of these land use bills make it easier than ever for homeowners to take advantage of this attractive opportunity.

For more information, click on "View our December 20, 2016 ADU Webinar"




What are the benefits of ADUs?

  • ADUs are an affordable type of home to construct in California because they do not require paying for land, major new infrastructure, structured parking, or elevators.
  • ADUs can provide a source of income for homeowners.
  • ADUs are built with cost-effective wood frame construction, which is significantly less costly than homes in new multifamily infill buildings.
  • ADUs allow extended families to be near one another while maintaining privacy.
  • ADUs can provide as much living space as many newly-built apartments and condominiums, and they’re suited well for couples, small families, friends, young people, and seniors.
  • ADUs give homeowners the flexibility to share independent living areas with family members and others, allowing seniors to age in place as they require more care.

What is HCD’s role in terms of ADUs?

HCD provides technical guidance to cities with sample ordinances and other resources and guidance. HCD will continue to develop tools and strategies to assist local governments in promoting ADUs.


Coming Soon!


MyADU will be a web-based resource and platform designed to support stakeholders interested in the construction or conversion of existing property into an Accessory Dwelling Unit. Homeowners across the state will be able to visit the site to get comprehensive “A to Z” support on the ADU construction process, and use the website as a platform to share their challenges and success stories with other homeowners through a moderated forum.

  • Financing Options for Local Governments
  • Ordinance Clearinghouse