STATEWIDE UPDATE: New California ADU Bills SB13, AB68, AB881, AB670 have passed. These laws will create more options for building an ADU in Campbell in 2020. To prepare for the upcoming changes use our ADU Services to learn how these laws will effect your property!
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Campbell ADUs

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Campbell ADU Guidelines Last Updated 08/11/19


The city government of Campbell has updated its local zoning codes to comply with the State ADU mandate.
The California Building Code (CBC) 2016 without amendments is adopted.
Relevant state bill updates for SB13, AB68, AB881, AB670 are shown in green below.


City Hint: The city has not yet responded to requests for ADU permit volumes for the past year, but they will be provided here once response has been received.


Number of ADUs allowed:

One ADU per primary home.

AB68 & AB881 Update: Properties which convert existing space to create ADUs may be eligible for one ADU -AND- one JADU.

Types of ADUs allowed:

Detached, Attached and junior ADU.

Lot size:

Minimum lot size. A parcel with a net lot area of ten thousand square feet or greater, inclusive of any public or private easements except for easements that establish a private street, subject to the living area or floorspace limitations specified by Table 3-1(a). The community development director may require preparation of a survey to verify the parcel size. minimum Net lot area Maximum Floorspace or LIVING area 10,000—10,999 square feet allows 700 square feet;11,000—11,999 square feet allows 800 square feet; 12,000—12,999 square feet allows 900 square feet; 13,000—13,999 square feet allows 1,000 square feet 14,000—14,999 square feet allows 1,100 square feet; 15,000 square feet or greater allws 1,200 square feet.

AB68 & AB881 Update: Properties will not be subject to minimum lot standards by ordinance or of the applicable zoning district.

ADU size:

Maximum size. The maximum floor space for a detached accessory dwelling unit and the maximum living area of an attached or interior accessory dwelling unit shall be as specified in Section 21.21.030.C, Table 3-1 (a), except that in no case shall the living area of an attached or interior accessory dwelling unit exceed fifty percent of the existing living area of the primary dwelling unit.

AB68 & AB881 Update: Properties will be allowed up to 850 square feet for a one bedroom or up to 1,000 square feet for a two bedroom ADU.


Setbacks are determined by the standards of the underlying zone.

AB68 & AB881 Update: The maximum required setback for a detached new construction ADU shall be no more than 4 feet from the rear or side property lines.


Compliant parking. A parcel that is presently developed with the minimum number of parking spaces required for a primary dwelling unit (one covered and one uncovered) or which will be developed with the required number parking spaces in conjunction with the creation of an accessory dwelling unit.

Parking. Off-street parking for accessory dwelling units, in addition to those parking spaces required for the primary dwelling unit (one covered space and one uncovered space), shall be provided in compliance with the following provisions.
Number of parking spaces required.
No additional parking shall be required for interior accessory dwelling units.
Attached and detached accessory dwelling units shall provide one parking space (covered or uncovered) per bedroom provided that any existing parking spaces that are removed by conversion of an existing garage shall be replaced concurrently with creation of the accessory dwelling unit.

Parking configuration. Required and replacement covered parking spaces created by construction of a carport or garage and replacement uncovered spaces shall comply with all applicable development standards. Uncovered parking spaces required for an accessory dwelling unit may encroach into a required front-yard or street-side yard setback within an existing driveway that satisfies the minimum stall dimensions for a residential parking space, unless such a configuration is determined not to be feasible based upon fire and/or life safety conditions present on the property. Such a determination may be appealed as an interpretation of this Code in compliance with Section 21.02.030 (Procedures for interpretations).

AB68 & AB881 Update: Properties which convert an existing garage will not be subject to replacement parking requirements.

Fire Safety:

Per state requirements.

Shape, materials and style:

Design. A detached accessory dwelling unit shall be constructed to incorporate the same or similar building materials and colors as the primary dwelling unit, except for manufactured homes which shall be required to incorporate only the same or similar building colors as the primary dwelling unit. Attached or interior accessory dwelling units shall maintain the appearance of the primary dwelling unit as that of a single-family dwelling. Garages that are converted to accessory dwelling units shall include removal of garage doors which shall be replaced with architectural features, including walls, doors, windows, trim and accent details that remove any appearance that the structure was originally a garage.


Maximum height and stories. A detached accessory dwelling unit shall be a maximum of fourteen feet in height and not exceed one story. An attached or interior accessory dwelling unit shall be limited to the ground floor or the basement of the primary dwelling unit.

Design review:

General requirements. Except as otherwise specified by this Chapter, all accessory dwelling units shall satisfy the requirements applicable to a primary dwelling unit, including required yards, building height, distance between buildings, setbacks, floor area RATIO, and lot coverage standards, as specified by the zoning district and/or area or neighborhood plan in which the parcel is located, as well as all applicable general performance, site development, landscaping, and parking standards (including those specified by Section 21.23.040.H). The requirements for accessory structures found in Section 21.36.020 (accessory structures) do not apply to accessory dwelling units.

The City shall issue a building permit for an accessory dwelling unit that is consistent with the provisions of this Chapter, as determined by issuance of a Zoning Clearance, within one hundred twenty days of submittal of a complete building permit application. However, physical expansion (i.e., addition) or exterior alteration to an existing primary dwelling unit located on a parcel that is subject to design review pursuant to Chapter 21.42 (Site and architectural review) or Chapter 21.33 (Historic preservation) shall first receive approval of the appropriate land use permit prior to a submittal of a building permit application for an accessory dwelling unit.

Number of Bedrooms:

Allowable rooms. Accessory dwelling units shall include no more than two bedrooms.


Rentals. No more than one dwelling unit on the parcel, either the accessory dwelling unit or the primary dwelling unit, shall be leased or otherwise rented. Leases for durations of less than thirty days, including short-term rentals (as defined by the California Government Code) are prohibited. The community development director shall require recordation of a deed restriction documenting these restrictions.

Subdivision and sales. No subdivision of land or air rights shall be allowed, including creation of a stock cooperative or similar common interest ownership arrangement.

SB13 Update: Owner-occupancy requirements for ADUs will be voided statewide for 5 years.

Utility connections:

Utilities. The Building Official shall coordinate with local utility agencies to ensure that accessory dwelling units are not considered new residential uses for the purpose of calculating local agency connection fees or capacity charges for utilities, including water and sewer services.


Exception to parking requirement. The parking requirement for an attached and detached accessory dwelling unit shall not apply in the following instances, which shall allow creation of an attached or detached accessory dwelling unit without provision of additional parking.
The accessory dwelling unit is located on a parcel within a traversable distance of one-half mile of public transit.
The accessory dwelling unit is located on a parcel within a designated historic district.
The accessory dwelling unit is located within the boundaries of a permanent residential parking permit program, and where the City does not offer parking permits to the occupant(s) of the accessory dwelling unit.
The accessory dwelling unit is located on a parcel within one block of a City-licensed car-share vehicle (as defined by the California Vehicle Code).


Entrances. An accessory dwelling unit shall include separate exterior access from the primary dwelling unit and may include an interior connection. However, the front door of an accessory dwelling unit shall not be oriented towards a public street. A passageway from the accessory dwelling unit to a public street may be created, but shall not be required by the City.

Allowed Zones:

Zoning district. A parcel located within an R-1 (Single-Family Residential) Zoning District.

AB68 & AB881 Update: ADUs will be allowed statewide in all single-family or multi-family zoning districts.


Existing primary dwelling unit. A parcel that is presently developed with one primary dwelling unit. An accessory dwelling unit may not be constructed on a parcel without a primary dwelling unit or which is developed with more than one primary dwelling unit.

Existing garages. An existing garage that is fully (not partially) converted to an accessory dwelling unit is subject to all provisions of this Chapter except that no additional setback from property lines or to other existing structures shall be required, provided that the existing garage is not expanded. Any expansion of the structure shall comply with applicable setback requirements and shall not be permitted to exercise the setback exception for non-conforming structures provided for in Section 21.58.050.F (Exceptions).

Demolition of an existing garage. When an existing garage (or carport) is demolished in conjunction with the construction of an accessory dwelling unit, any required parking spaces contained within the garage (or carport) shall be replaced concurrently with creation of the accessory dwelling unit. The replacement spaces shall comply with all applicable development standards except that the replacement spaces may be located in any configuration on the parcel, including, but not limited to, as covered spaces, uncovered spaces, or tandem spaces, or by the use of mechanical automobile parking lifts.

SB13 Update: Amnesty program to permit unpermitted units will be administered statewide, allowing non-health and safety code violations to be deferred.

Kitchen / Bath:

Two bathrooms. In no case shall an accessory dwelling unit include more than one kitchen.

Building Code:

Building code. Accessory dwelling units shall comply with all applicable Building and Fire Codes as appropriate, except that the Building Official shall not require installation of fire sprinklers for an interior accessory dwelling unit if they would otherwise not be required for the primary dwelling unit, except if the creation of the accessory dwelling unit would result in creation of a "new dwelling using portions of the original structure" pursuant to Chapter 18.32 (Determination of scope of work).

Residential Building Code:

The California Building Code (CBC) 2016 without amendments is adopted.

Campbell City Planning Offices

Campbell Planning Division

70 N First St. Campbell, CA 95008 Campbell, CA 95008

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Realty One Group

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[CA] Governor Brown Issues Legislative Update 2017-10-08

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Appreciation Estimate = (Base Value: $) / (Home's Living Space: sqft) * (ADU's Living Space: sqft)

Rental Estimate = (Rent Per Sqft: $4.27) * (ADU's Living Space: sqft)

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