Accessory Dwelling Units (ADUs)

The ADU ordinance permits one accessory dwelling unit in all residential zoning districts, subject to the following:

1) The accessory dwelling unit must be located on the same lot as a single-family dwelling (existing or proposed)

2) The accessory dwelling unit cannot exceed one-third (1/3) of the floor area of the main single-family dwelling or 500 square feet, whichever is greater.  Please see the definition below in order to calculate floor area: 

       Floor area means the sum of the horizontal areas of enclosed building space on all floors of all buildings on a lot measured from the exterior face of exterior walls and including intervening partitions, halls, lobbies, stairways and elevator shafts. The following shall be excluded from calculation of floor area:

• Open exterior balconies and other unenclosed spaces
• Uncovered terraces, patios, porches, or steps
• Garages, carports or other areas, enclosed or unenclosed, used for the parking or circulation of motor vehicles
• Areas for housing major mechanical equipment which serves the building as a whole or major portion thereof, but not including utility areas within individual dwelling units
• Areas for common special purpose use by occupants of the premises, including laundries, recreation areas, sitting areas and libraries in buildings devoted to dwelling use, and storage areas, and areas devoted exclusively to management and/or maintenance of the premises in buildings devoted to any use, but not including incidental commercial activities in any case.

3) The accessory dwelling unit must follow the underlying zoning district requirements (setbacks, lot coverage, height, etc.).  If the ADU is detached from the main dwelling, the accessory building is subject to the requirements of Article VI, Division 9 of the Zoning Ordinance.  In addition, access to an accessory building with an accessory dwelling unit shall be provided in accordance with requirements of the Department of Public Works and Department of Fire and Emergency Services.

In addition to the zoning regulations, there are building code regulations that are required for ADU approval.  Click HERE to learn more about the building code regulations and the building permit submittal process.