Second Units in the City of Dublin

Dublin refers to “Second Units” instead of ADUs.  The City has produced a brochure describing its regulations.

Key design Issues:

  • Maximum of one second unit per lot.
  • The total floor area of a second unit shall be not less than 275 square feet, nor more than 1,200 square feet.
  • The second unit shall conform to the development standards of the R-1 zoning district.
  • The second unit shall provide one off-street parking space in accordance with the requirements of Chapter 8.76, Off-Street Parking and Loading, of the Zoning Ordinance, with exceptions.
  • Second units shall be served by public water and sewer and shall have access to an improved public street.
  • Design compatibility with the existing single-family residence.
  • The entrance of a second unit shall not be visible from the street.
  • The second unit and the principal residence combined shall not cover more than 60% of the lot.
  • The second unit, if attached, shall not exceed 50% of the floor area of the existing residence.
  • The second unit shall conform to the building setback requirements.

The Dublin Building Department can be reached here.