STATEWIDE UPDATE: New California ADU Bills SB13, AB68, AB881, AB670 have passed. These laws will create more options for building an ADU in Fremont 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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Last Updated 08/11/19


The city government of Fremont has updated its local zoning codes to comply with the State ADU mandate.
The California Building Code (CBC) 2016 is adopted with the following amendment(s): 20-2016 to 21-2016, 42887, 05-2017 CALGreen
Relevant state bill updates for SB13, AB68, AB881, AB670 are shown in green below.


City Hint: The city permitted a total of 34 ADU project(s) in the past year of 2018, which is below the average compared to other cities in California.


Number of ADUs allowed:

On lots where ADUs are allowed, only one ADU per lot is permitted.

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

Types of ADUs allowed:

There are two types of ADU’s, Standard accessory dwelling units (SADUs) and Junior Accessory dwelling units (JADUs). SADUs may be detached structures on the property, or can be attached to the primary dwelling. They usually result in an increase in habitable floor space on the property when they are created. JADUs are created from existing habitable space (such as a bedroom) and are smaller than 500 square feet.

Lot size:

ADUs are not permitted on lots larger than 7,500 square feet in the R-G zoning district or on lots larger than 6,000 square feet in the R-3 zoning district.

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

ADU size:

The maximum ADU size is determined by the lot area (square footage) of the property. For lots less than 5,000 square feet, 500 square feet maximum ADU size; For lots between 5,000 to 7,999 square feet, 700 square feet maximum ADU size; For lots between 8,000 to 9,999 square feet, 800 square feet maximum ADU size; For lots between 10,000 to 19,999 square feet, 900 square feet maximum ADU size; For lots between 20,000 to 39,999 square feet, 1,050 square feet maximum ADU size. For lots 40,000 square feet or more, 1,200 square feet maximum ADU size.

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.


If a detached structure, the ADU must be separated from other habitable structures on the lot by at least 10 feet. This may be reduced to eight feet if one structure is equipped with fire sprinklers or six feet if both structures are equipped with fire sprinklers.

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.


One parking space per bedroom is required for an SADU, except that no parking is required where the ADU meets any of the following criteria:
1) The SADU is located within ½ mile (measured by actual walking distance) of public transit, including BART stations, the ACE Station in Centerville, and bus stops on “major transit spines” as defined by Fremont General Plan Diagram 3-6.
2) The SADU is located within the Mission San Jose or Bryant Street Conservation Areas, or on a property that includes a historic register resource or potential historic register resource.
3) The SADU is located entirely within the existing principal residence and adds no habitable floor space to the property.
4) The SADU is located in an area where on-street parking permits are required, but are not offered to the occupants of the SADU.The SADU is located within one block of a designated parking area for one or more car share vehicles available to the general public by subscription.

Note: If requesting a waiver from parking requirements, the applicant must submit evidence that the property meets one of the criteria above. Where a parking space is required, it may be provided through any of the following methods:
1) Conventional garages or carports
2) Uncovered paved areas such as extended driveways
3) Tandem parking
4) Parking on other locations on the property (including within the setbacks), unless specific findings are made that parking in these areas is not feasible based on life safety conditions.

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

Fire Safety:

If a detached structure, the ADU must be separated from other habitable structures on the lot by at least 10 feet. This may be reduced to eight feet if one structure is equipped with fire sprinklers or six feet if both structures are equipped with fire sprinklers. Other exceptions may apply.

Shape, materials and style:

ADUs shall incorporate architectural features, building materials and colors that are compatible with the principal residence.
1. Outside stairways to the ADU shall not be in the front of the principal residence.
2. A continuous paved pathway from the street to the front door of the ADU (called a “passageway”) may be added, but is not required.


ADUs may not exceed the building height limits applicable to the principal residence.

Design review:

An application for an ADU that meets the applicable standards in the Fremont Municipal Code (FMC) is subject only to ministerial review and approval. This means that the application may be approved by staff and no public hearing is required. Where design review requirements are applicable (for example, for an addition or a new detached structure), a Ministerial design review Permit is required.

Number of Bedrooms:

Not specified by State Standards.


The legal owner of the property must reside on the property, either in the principal residence or in the ADU. An ADU may not be rented for a term of less than 30 days.
A deed restriction must be filed with Alameda County prohibiting the sale of the ADU as a separate residence, and verifying that the unit complies with The City’s requirements.

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

Utility connections:

Permits from the Alameda County Water District (ACWD) and Union Sanitary District (USD) may also be required. A fee is required for the building permit and may be required for other permits.

Permit Fees

SB13 Update: Local impact fees for ADUs will be reduced substantially statewide.


Accessory Dwelling Units (ADUs—also known as “secondary dwelling units” or in-law apartments) are attached or detached residential dwelling units that are subordinate to a principal residence on the same lot and that provide complete independent living facilities for one or more persons. ADUs include permanent provisions for living, sleeping, eating, cooking, and sanitation.

Historic Requirements:

On lots that have been deemed eligible or formally listed on the National Register of Historic Places, the California Register of Historical Resources, or any adopted local list of historic resources, architectural approval must be granted by the Historical Architectural Review Board (HARB).


ADUs do not count toward the density requirements in the General Plan or zoning regulations.

Allowed Zones:

ADUs are not permitted in duplexes, triplexes, and other buildings with more than one principal residence.

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


Note: ADUs are not allowed on “constrained” land, where development capacity is limited because of conditions determined to be detrimental to public health, safety and welfare, such as soil instability or severe slopes. In such areas, ADUs may be located only within the area of the lot allowed for the principal residence.

Residential Building Code:

The California Building Code (CBC) 2016 is adopted with the following amendment(s): 20-2016 to 21-2016, 42887, 05-2017 CALGreen

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39550 Liberty St. Fremont, CA 94538 Fremont, CA 94538

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* based on local average price per sqft


* estimated by location


* 30 years / 5% interest rate / 20% down payment


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

Rental Estimate = (Rent Per Sqft: $3.96) * (ADU's Living Space: sqft)

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