San Ramon, CA

Accessory Dwelling Unit (ADU) City Regulations

Are ADUs allowed in San Ramon:


Number of ADUs allowed:

ADUs are limited to one per primary dwelling.

Types of ADUs allowed:

Detached, attached and junior ADUs are all permitted.

Lot size:

Refer to state minimum requirements.

ADU size:

Both attached and detached ADUs must be a minimum 150 sq. ft. in size. Attached units can be no more than 50% of the habitable area of the existing primary dwelling and are limited to 1,200 sq. ft. A detached unit also is limited to 1,200 sq. ft. in size.


In all R zones or a PD zone, attached ADUs must conform to the setbacks applicable to the underlying residential zone. In the RS-6 and RS-7 zones, a detached one-story secondary unit must be set back at least 20 feet from the front property line, five feet from the interior side property lines, seven feet from the corner side property line, and seven feet from the rear property line. In all other R zones or a PD zone, the same setbacks apply with the exception of a setback of seven feet from the interior side property lines.


A single additional parking space in the driveway generally meets the parking requirements for ADUs.

Fire Safety:

Refer to the state minimum requirements.

Shape, materials and style:

Building materials, colors and exterior finishes should be mostly the same as those on the existing dwelling and be harmonious with the rest of the neighborhood. Access to the ADU shall not be in the front of the existing dwelling and should not be visible from the front or street.


Should follow guidelines to residential construction in the applicable zone.

Design review:

Must follow ministerial review per state standards.


Either the main dwelling or ADU must be owner occupied.

Allowed Zones:

ADUs are allowed in the RC, HR, RE, RS, RM, RMH, and in PD zones for residential uses on lots with existing or planned single-family dwelling.


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