Accessory Dwelling Units (ADUs)
What are ADUs?
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.
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.
New laws effective January 1, 2018
These bills, effective January 1, 2018, will clarify and improve various provisions of the law to promote the development of ADUs, including allowing ADUs to be built concurrently with a single-family home, opening areas where ADUs can be built to include all zoning districts that allow single-family uses, modifying fees from special districts, and reducing parking requirements.
Current state laws for ADUs
State legislation that took effect January 1, 2017 gave California cities more flexibility and latitude for allowing homeowners to build ADUs. Three separate bills were introduced and signed by Governor Brown; 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.
Webinar : Recent Legislation "Nuts and Bolts"
Technical Assistance Booklet
Download entire booklet (PDF)
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:
New! Updated ADU booklet coming soon!
City and county ADU ordinances
Cities and counties are not required to create ordinances for ADUs; however, any city/county that does adopt an ADU ordinance, must submit the ordinance to HCD within 60 days. Failure to submit ADU ordinances to HCD within 60 days of adoption will result in a default to state ADU laws. The spreadsheet below includes all ordinances submitted to HCD as of August 21, 2017.
Sample materials from cities and counties
- ADU flyer (PUB) - Sonoma County
- Junior ADU flyer (PUB) - Sonoma County
- Junior ADU pamphlet (PDF) - Sonoma County
- ADU guidebook - City of Los Angeles
- ADU General Info Trifold (PDF) - Healdsburg
- ADU General Info Trifold (PUB) - City of Dublin
- ADU General Info Trifold (PDF) - City of Fremont
- California State Fire Marshal (PDF) - Information bulletin regarding sprinkler system requirements.
- CalHFA (PDF) - Bulletin for ADU income which includes anticipated income from planned ADU to qualify for loan to create the ADU.
- California Department of Housing and Community Development (PDF) - Information Bulletin providing clarification and outlining provisions of various residential types, ranging from recreation vehicles and manufactured homes to site-constructed California Building Standards Code dwellings.
- For ADUs in Coastal Commission areas:
- ADU guidance memo for planning directors in coastal cities and counties (PDF) - April 18, 2017
- ADU guidance memo update (PDF) - November 20, 2017
- Lilypad Homes - Resources to facilitate the development of accessory dwelling units that offer a more affordable housing option for both homeowners and renters. (Novato, CA)
- Accessory Dwellings - One-stop resource about accessory dwelling units. (Portland, OR)