ADU Typologies and Resources

What is an ADU? 

An ADU is accessory to a primary residence and has complete independent living facilities for one or more persons and has a few variations:

Detached Garage Addition

Detached Garage Addition

Detached Ground Up

Detached Ground Up

Detached Garage Conversion

Detached Garage Conversion

Jr. ADU / Attached Addition

Jr. ADU / Attached Addition

Jr. ADU Attached Conversion

Jr. ADU Attached Conversion

Attached Conversion

Attached Conversion

  • Detached: The unit is separated from the primary structure.

  • Converted Existing Space: Space (e.g., master bedroom, attached garage, storage area, or similar use, or an accessory structure) on the lot of the primary residence that is converted into an independent living unit.

  • Attached: The unit is attached to the primary structure.

  • JADU: A specific type of conversion of existing space that is contained entirely within an existing or proposed single-family residence.

  • Multi-Family ADU: In multi-family projects, Local agencies must allow up to two new constructed Detached ADU's and/or Multiple ADU's within the portions of multifamily structures that are not used as livable space, such as attached garages. Maximum allowable conversion units are up to 25% of the existing dwelling units.

For more information, please see the list below of CA State Resources for ADUs.