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Fremont, California: ADU Regulations

Date Updated:



ADUs allowed in all single-family and multi-family districts, unless otherwise stated.

Number of ADUs allowed:

On approved lots, only one ADU is permitted.

Types of ADUs allowed:

Attached and Detached Standard ADU (SADU), Junior ADU (JADU)


Attached ADUs may not exceed the one- and two-story building height limits applicable to the principal residence or 16 feet in height, whichever is greater.

Lot size:


Maximum ADU Area:

JADU: 500 sq.ft. in size.
An ADU that is on a lot with a primary two-family dwelling or multiple dwelling shall not exceed 1,000 square feet.

Attached: 50% of the floor area of the primary residence or 850 sq.ft. (studio or one-bedroom) or 1,000 sq.ft. (two bedrooms or more).
Detached ADUs: 1,000 sq.ft. (lots smaller than 10,000 sq.ft.); 1,200 square feet (lots > 10,000 sq.ft.).

Lot Coverage:



No min/max


SADUs must have a separate and complete kitchen

JADUs must include an efficiency kitchen, not located within a closet.


SADUs must have separate sanitation facilities.

JADUs may include a bathroom or share bathroom facilities within the primary dwelling.


SADUs shall maintain a 4' minimum setback from rear and side property lines. Garage conversion SADUs are exempt from setback requirements provided any walls within the setback area comply with applicable building and fire codes.


For JADU there are no additional parking spaces required. SADUs require one parking space (garage or carport, paved extended driveway, or other location on the property) per bedroom unless the unit is located within one-half mile of public transit (BART stations, Centerville's ACE Station, or bus stops) or one block of a public subscription car share parking lot, is within the Mission San Jose or Bryant Street Conservation Areas, is on an historic register resource property, or is located in an area where on-street parking permits are required but are not offered to ADU occupants.


Detached: 16’ except when a lawfully existing structure is converted to an ADU, or where an ADU is constructed to replace a lawfully existing structure in the same location and to the same dimensions.
Attached: the building height limitation applicable to the primary dwelling on the lot.


Not included in current municipal code
ADUs can only be located within the area of the lot allowed for the principal residence.
JADU shall be constructed entirely within the existing walls of an existing single-family home.

Rear Yard Coverage:

Not included in current municipal code


All ADUs must have a separate exterior entrance that cannot be located on the front of the primary dwelling. Outside stairways to the ADU shall not be located in the front of the primary dwelling. JADUs also require interior access to the primary dwelling and may be a door with a double lock. Interior access between the JADU and the primary residence is not required unless necessary for access to shared sanitation facilities, and can be a door equipped with a double lock. A second interior doorway may be provided for sound attenuation.


ADUs shall comply with objective design rules in the Citywide Design Guidelines, or other adopted underlying design guidelines, and the Fremont Municipal Code pertaining to building design, architectural elements, materials and colors, and privacy. Outside stairways to the ADU shall not be in the front of the primary residence. A permanent foundation shall be required for all detached ADUs. On lots located in a Hillside Combining (H-I) district, ADUs shall be subject to the development standards in Section 18.130.050. On lots located in an Open Space (OS) district, ADUs shall be subject to the performance standards in Section 18.55.040.

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

Historic Requirements:

Architectural approval must be granted by the Historical Architectural Review Board for lots on the National Register of Historic Places, the California Register of Historical Resources, or any local list of historic resources.

Source Code:

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!