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Accessory Dwelling Units (ADU)


ADU’s are defined as a separate dwelling unit within a single-dwelling or a separate structure associated with a single-family dwelling which is incidental and subordinate to the primary residential use of property.  

Accessory dwelling units can either be:

  1. Detached. Those accessory dwelling units that are lawfully constructed within existing outbuildings, or stand alone, where the ADU does not share a common wall with the primary residential dwelling unit. ADUs that are connected to a primary residential structure only by a covered breezeway or similar appurtenant structure shall be considered detached.
  2. Attached. Those accessory dwelling units that share a common wall or floor/ceiling with the primary dwelling unit and do not meet the definition of detached accessory dwelling unit.

The size of a detached ADU shall not exceed fifty (50) percent of the gross floor area of the primary dwelling unit, nor exceed 1,250 square feet in gross floor area.  Attached ADUs shall not exceed thirty-five (35) percent of the gross floor area of the primary dwelling unit.

Not every parcel qualifies for an ADU. Eligibility depends on the Zoning designation of the parcel and the size of the parcel.  For detailed information see Text of Accessory Housing CCC 33.50

Requirements for an Accessory Dwelling Unit include:

  • An approved Building Permit for new construction or modification of existing structures to serve as a dwelling.
  • Compliance with ADU design standards, including but not limited to size of structure.  An ADU worksheet will need to accompany your Building Permit application.
  • A single entrance serving both dwellings and on-site parking provided.   
  • The owner of the parcel must live either in the primary dwelling or the ADU as their primary residence.

A Notice to Title (link coming soon) will also be required to be recorded.

Additional standards are addressed for accessory apartments in commercial and industrial zones, and for temporary medical hardship dwellings. See Text of Accessory Housing CCC 33.50 for additional information.