Accessory Dwelling Units in Fremont are covered under Fremont Municipal Code Section 18.190.005


  • On lots where ADUs are allowed, only one ADU per lot is permitted.
  • 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.
  • ADUs are not permitted in duplexes, triplexes, and other buildings with more than one principal residence.
  • 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.
  • ADUs do not count toward the density requirements in the General Plan or zoning regulations.
  • ADUs may be located only within the area of the lot allowed for the principal residence.
  • ADUs may not exceed the building height limits applicable to the principal residence.
  • ADUs may be located entirely within the existing residence, attached to the existing residence, or detached in a separate structure. 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.


  • 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.


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


  • Minimum size is 150 sq.ft.
  • For a parcel size less than 5,000 sq.ft, an ADU of 500 sq.ft. can be built.
  • For a parcel size between 5,000 and 7,999 sq.ft, an ADU of 700 sq.ft. can be built.
  • For a parcel size between 8,000 and 9,999 sq.ft, an ADU of 800 sq.ft. can be built.
  • For a parcel size between 10,000 and 19,999 sq.ft, an ADU of 900 sq.ft. can be built.
  • For a parcel size between 20,000 and 39,999 sq.ft, an ADU of 1,050 sq.ft. can be built.
  • For a parcel size more than 40,000 sq.ft, an ADU of 1,200 sq.ft. can be built.

One parking space per bedroom is required for an ADU, except that no parking is required where the ADU meets any of the following criteria:

  • The ADU is located within 1⁄2 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.
  • The ADU 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.
  • The ADU is located entirely within the existing principal residence and adds no habitable floor space to the property.
  • The ADU is located in an area where on-street parking permits are required, but are not offered to the occupants of the SADU.
  • The ADU is located within one block of a designated parking area for one or more car share vehicles available to the general public by subscription.