ADU Handbook
Updated January 2026.
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Accessory Dwelling Unit Portal
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Image of accessory dwelling unit in a back yard.

Accessory Dwelling Units (ADUs) and Junior Accessory Dwelling Units (JADUs) are an innovative and effective option for adding much needed housing in California.

ADUs have been known by many names: granny flats, in-law units, backyard cottages, secondary units and more. HCD is the state’s leader on local ADU ordinances, which — while optional — have grown exponentially in number as more cities, counties, and homeowners become interested in ADUs as one solution to increasing the supply of affordable housing.

As of March 25, 2024, with the Chaptering of Senate Bill (SB) 477 (Chapter 7, Statutes of 2024), the sections of Government Code relevant to State ADU and JADU Law have been re-numbered.

Submit an Ordinance/View TA and Ordinance Review Letters
Submit an Ordinance/View TA and Ordinance Review Letters
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Additional Resources
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