Development standards for Accessory Dwelling Units are located in Brisbane Municipal Code Chapter 17.43

Summary: Newly Constructed Accessory Dwelling Units:

A newly constructed accessory dwelling unit shall be established or occupied only by an accessory dwelling unit permit granted by the director of community development pursuant to the provisions of this subsection as a ministerial act, in accordance with Section 65852.2 of the California Government Code. An existing nonconforming dwelling unit may be designated as an accessory secondary dwelling unit subject to compliance with the requirements of this subsection.

Newly constructed accessory dwelling units shall comply with all of the following development standards:

1. Zoning Districts. Accessory dwelling units may only be established or occupied in the R-1 residential district or the R-BA Brisbane Acres residential district.

  1. Lot Size. If the lot is located in the R-1 District, there is no minimum lot size requirement. If the lot is located in the R-BA Brisbane Acres residential district, a minimum lot size of twenty thousand (20,000) square feet is required.
  2. One Accessory Dwelling Unit per Site. Only one accessory dwelling unit shall be permitted on any one site; provided, however, where a site already contains two or more dwelling units that exist as legally established nonconforming uses, no additional accessory dwelling units shall be allowed on that site.
  1. Attached or Detached. The accessory dwelling unit may be attached to or constructed within the main dwelling or may be detached from the main dwelling on the site.
  2. Unit Size. The accessory dwelling unit shall not exceed one thousand (1,000) square feet in floor area.
  3. Floor Area Ratio. The floor area of the accessory dwelling unit shall be included in calculating the floor area ratio for the site on which the accessory dwelling unit is located.
  4. Parking. Parking spaces for the main dwelling and accessory dwelling units shall be provided in accordance with the requirements set forth in Chapter 17.34.
  5. Access. As required by Section 17.01.060 of the Municipal Code, the site on which the accessory dwelling unit is located shall have a legal means of access that complies with the street standards set forth in Section 12.24.010.
  6. Utilities. The site is served by adequate water, sewer, and storm drain facilities which comply with city standards. An accessory dwelling unit shall not be considered a new residential use for the purposes of calculating connection fees or capacity charges for water and sewer service provided by the City.
  7. Compliance with Codes. The accessory dwelling unit and all new construction on the site that will be performed in connection therewith shall comply with all applicable provisions of this title and all applicable building, health and fire codes, with the following exception:  Accessory dwelling units shall not be required to provide fire sprinklers if fire sprinklers are not required for the main dwelling, as determined by the Building Official consistent with BMC Section 15.08.140.

Conversion Accessory Dwelling Units: Notwithstanding subsection A of this section 17.43.020, an accessory dwelling unit resulting from the conversion of existing building space shall be established by a City issued building permit and shall be exempt from the development standards of 17.43.020.A if it meets the following requirements, as determined by the Community Development Director:

  1. It is contained within the existing space of a single-family dwelling or accessory structure, as defined in Chapter 17.02, within a single-family residential zone; and
  2. It has an independent exterior access from the existing residence; and
  3. It has sufficient side and rear setbacks for fire safety.


City of Brisbane

City of Brisbane Community Development Department