The legal term is Accessory Dwelling Unit, or ADU. ADUs go by many names - granny flats, granny units, in-law apartments, or secondary suites - just to name a few. ADUs are a permanent structure that provides a fully-appointed living space in the backyards of existing homes. ADUs typically have at least 1 bedroom, 1 bathroom and a kitchen space.
Accessory Dwelling Units (ADUs) have been 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. 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.