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San Rafael, California: ADU Regulations

Date Updated:

San Rafael is still in process of alignment with new state regulations


Any lot zoned for single-family or multifamily use that contain an existing single-family residence. No JADUs on multi-family.

Number of ADUs allowed:

Single-family zones: One Attached or Junior, and one Detached (if JADU)

Multi-family zones: At least one ADU within existing structure (max is 25% of existing multi-family units), and two Detached

Types of ADUs allowed:

Detached, attached, and junior ADUs are all permitted. 

Lot size:


Maximum ADU Floor Area:

There is no square footage limit for existing space. If you are adding square footage to create an ADU, the square footage of the unit cannot exceed 50% of the main residence. Detached ADU cannot exceed 1,200 sq.ft.

Junior ADUs must not exceed 500 sq.ft.

Minimum ADU Size:

In a single-family residence: The floor area of the ADU should have at minimum a combined living, eating and sleeping room not less than 70 sq.ft.. For a multifamily residence, an ADU should contain at minimum combined living, eating and sleeping room not less than 150 sq.ft.. In both cases, any additional habitable rooms should be a min of 70 sq.ft. and not less than 7 ft. in any direction.

Lot Coverage:

Must comply with existing zoning requirements for the lot on which the ADU is planned.


No min/max


No min/max


Attached and Detached ADUs must provide complete and independent cooking and eating provisions.
Junior ADU must include a food preparation area, and there are no longer sink size or electrical/gas/propane connections restrictions.


Attached and Detached ADUs must provide complete and independent sanitation facilities.

Junior ADU may share water and sewer service with the primary residence.


Attached ADUs are subject to the same setback requirements of the principal dwelling. Detached ADUs are subject to the setback requirements applicable to any accessory structures, plus 4' side and rear setbacks.


ADUs require at least one parking space for a single bedroom, and one additional space for units with two or more bedroom. JADUs do not require parking.

Required parking options are as follows:
a. One (1) parking space for a second dwelling unit may be sited in the front yard setback provided that: 1) the parking space is located within a paved area adjacent and parallel to the driveway, between the driveway and the nearest side lot line; and 2) the curb cut is not increased.
b. One (1) required space for the second dwelling unit may be uncovered and tandem (located behind another uncovered or covered parking space) on a driveway having a length of at least eighteen feet (18') behind the sidewalk or property line, provided the property has frontage on a street having a paved width of at least thirty-eight feet (38').
c. Off-street parking for the second dwelling unit that requires a new driveway curb cut, either for establishing an additional driveway or for increasing the width of the existing curb cut, may be proposed subject to an affirmative recommendation by the public works department and the approval of an environmental and design review permit by the zoning administrator. The purpose of this permit review is to ensure that the alternative parking design is appropriate given the site conditions, is compatible with the character of the surrounding residential neighborhood, and would not result in a safety hazard to vehicles or pedestrians.

Fire Safety:

Must follow state requirements. Sprinklers not required if not required for primary residence. However, if the addition of the ADU incorporates a remodel of more than 50% of the main residence, then sprinklers will be triggered for both the main residence and the ADU.

Note: Fire Department regulations should be assessed on a project by project basis.


Attached ADUs are subject to the height requirements applicable to the primary dwelling.
Detached ADUs located in side or rear setback areas shall not exceed 16' unless approved and permitted by the planning commission.

Rear Yard Coverage:

ADU must comply with the coverage regulations applicable to the lot on which it is located.

Design review:

Unclear until the City issues new regulations

Note: Historic Neighborhoods or Districts should be assessed on a project by project basis.


For Attached and Detached ADUs separate entrances from the primary dwelling are required and may not be located on the same exterior building elevation which is most parallel to the front property line.
For Junior ADUs a separate exterior entry shall be provided, additionally interior access to the primary dwelling is required, and can be a door with a double lock.

Owner Occupancy:

Owner-occupancy is still required for a JADU but not for an ADU

Source Code:

Important Note: Rules and regulations are updated and changed frequently. It’s one of our jobs to be up to speed and navigate those regulations. Let us know if our website isn’t up to date or if you have any information that could help. Cheers!