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Campbell, California: ADU Regulations

City or County:

Campbell, California

Date Updated:




Types of ADUs:

Attached, Detached, Garage Conversion


Single story

Lot Size:

Min. 10,000 sq.ft.

Maximum ADU Floor Area:

Lot Size

Max Floor Area

10,000—10,999 sq.ft.

700 sq.ft.

11,000—11,999 sq.ft.

800 sq.ft.

12,000—12,999 sq.ft.

900 sq.ft.

13,000—13,999 sq.ft.

1,000 sq.ft.

14,000—14,999 sq.ft.

1,100 sq.ft.

+15,000 sq.ft.

1,200 sq.ft.

Note: in no case shall living area for attached or interior ADU exceed 50% of existing primary dwelling unit.

Lot Coverage:

Must comply with standards of underlying zoning district.


Max. 2 bedrooms


No min/max


Max 1 kitchen (with permanent provisions for cooking and eating)


Max. 2 bathrooms

Note: Drainage and sewer connections should be assessed on a project by project basis.


  1. Interior ADU: no additional parking required.
  2. Attached/Detached ADU: one parking space per bedroom; exceptions apply.
  3. Garage Conversion: any existing parking spaces that are removed by conversion to be replaced concurrently with the creation of accessory dwelling unit.

Uncovered parking spaces required for accessory dwelling unit may encroach into required front-yard or street-side yard setback within existing driveway that satisfies the min. stall dimensions for a residential parking space, unless such configuration is determined not to be feasible based upon fire and/or life safety conditions present on property.

Parking Exceptions:

No parking space is required if unit:

  1. Is located within one-half mile of public transit.
  2. Is located within a designated historic district.
  3. Is located within boundaries of permanent residential parking permit program, and where the City does not offer parking permits to the occupant(s) of the ADU.
  4. Is located within one block of a City-licensed car-share vehicle.


Attached/Detached: must comply with minimum requirements of zoning district.

Note: Fire Department regulations should be assessed on a project by project basis.


Attached: must comply with standards of underlying zoning district.

Detached: single story 14' max


Attached or interior ADU limited to the ground floor or the basement of the primary dwelling and must maintain appearance of primary dwelling as that of a single-family dwelling. Spacing between structures and lot coverage guidelines of zoning district apply.

Rear Yard Coverage:

Must comply with maximum allowable yard coverage of zoning district.


Detached must incorporate same or similar building materials and colors as primary dwelling, except for manufactured homes, which are required to incorporate only same or similar building colors as the primary dwelling.

ADUs converted from garages to include removal of garage doors, to be replaced with architectural features that remove any appearance that structure was originally a garage.

Note: Historic Neighborhoods or Districts should be assessed on a project by project basis.


Must include separate exterior access from primary dwelling. Front door cannot be oriented towards public street.

Code Source:

Important Note: Rules and regulations are updated and changed frequently. It’s one of our jobs to be up to speed and navigate those regulations. Let us know if our website isn’t up to date or if you have any information that could help. Cheers!