Second dwelling units, also known as mother-in-law or granny units, are an important part of a city’s housing stock. They can provide lower-cost housing and independent living for elderly parents and teenagers, or can be rented for additional income to help with mortgage payments.
The State of California requires that cities allow for second dwelling units in their zoning regulations. The City of San Rafael’s regulations are contained in Section 14.16.285 of the Municipal Code
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The City’s General Plan 2020 encourages second units as a means of increasing our affordable housing stock, distributed in scattered units throughout the community.
What constitutes a Second Dwelling Unit?
A second dwelling unit contains separate living quarters from the main dwelling “for the exclusive use of one household, with a kitchen, sleeping facilities, and sanitary facilities”. A kitchen is defined as an area for “the storage, preparation and cooking of foods with proximal arrangement of two or more of the following: a sink, food storage and preparation areas, a refrigerator or cooking appliances (including a stove, microwave or convection oven, cooking burners, etc.). A second dwelling unit may be either part of the main dwelling or can be in a detached accessory building. The second dwelling unit must have a separate entrance from the main dwelling.
Which lots can qualify for a Second Dwelling Unit?
To qualify for a second unit, a residential lot must be at least 5,000 square feet in size and must have an existing dwelling unit on the property. The property owner must reside on the property, but can rent out either the main dwelling or the second dwelling unit. In addition, a deed restriction must be filed with the County Recorder indicating the zoning limitations associated with the second unit.
How large can a Second Dwelling Unit be?
The size of the second dwelling unit cannot exceed 40% of the gross square footage of the main dwelling, not including the garage, but can be at least 500 square feet. A second dwelling unit up to 800 square feet can be approved at a staff level without a public hearing, and a unit up to 1,000 square feet can be approved by the Planning Commission through issuance of a Use Permit.
How much parking is required?
A studio or one-bedroom unit requires one additional parking space, and a two-bedroom or larger unit requires two additional spaces. This parking can be uncovered. One parking space may be located on a paved area between the driveway and a side lot line. On lots with frontage on wider streets (with a paved width of at least 38 feet), one of the parking spaces may be tandem, located in front of the garage or carport, on a driveway with at least 18 feet to the sidewalk.
What permits are required?
Most second dwelling units can be approved by Planning Division staff prior to submittal for a building permit if the plans show that the unit:
- Provides required parking,
- Does not exceed 40% of the gross square footage of the main dwelling, up to a maximum of 800 square feet,
- Does not entail a building addition above the ground floor of the main dwelling or in a detached accessory building taller than 15 feet,
- Is not located in a detached accessory structure within side and rear setbacks required for the main dwelling, and
- Meets all other Zoning Code requirements.
There is a $300 fee for this zoning compliance check, which involves a site visit by a City planner.
Issuance of a Use Permit following a public hearing before the Planning Commission is required for proposed second dwelling units which are:
- Between 800 and 1,000 square feet, or
- Are located in a detached accessory building within required side or rear setbacks, or
- Are above 15 feet in height.
Approval of an Environmental and Design Review Permit by the Planning Commission and possible review by the Design Review Board is necessary for proposed second dwelling units that:
- Entail new construction above the ground floor which results in modifications to the exterior of the structure, or
- Are located in new or remodeled detached accessory buildings within required side or rear setbacks.
How can an existing second dwelling unit that was created without permits be legalized?
First, check with the Building and Fire Prevention Division on the 3rd floor of City Hall to view the property address file to check for old building permits. There also may exist former resale inspection results that identify the number of dwelling units present at the time or identify a possible illegal unit.
To determine whether an older second dwelling unit is legal based on grandfathered rights (i.e., was built prior to the adoption of zoning regulations for second units) it is critical to pinpoint the age of the second dwelling unit (or kitchen components) and then to determine whether the second unit was in compliance with zoning and building permit requirements in effect at the time it was built. There are no zoning compliance issues with second units whose construction dates can be verified prior to 1950. It may be difficult to determine building permit compliance since there are no City building permit records that pre-date 1947.
To provide evidence that a second dwelling unit was constructed prior to 1950, provide dated photographs, utility bills, rental receipts, tax records, building permits, construction contracts or any other documents that clearly establish the construction date of the unit. The information must verify the existence of a separate dwelling unit including a kitchen, bathroom and sleeping area. A site plan showing the location of the second unit and any other structures on the site must also be submitted.
If documentation of construction prior to 1950 cannot be provided, the unit may be legalized if it meets the requirements for second units as described above and obtains a building inspection to verify code compliance. Building permit fees for legalization of unpermitted units are tripled.
Where can I obtain more information?
A handout is available from the Planning Division which describes the regulations pertaining to second dwelling units in greater detail. Application forms and a fee schedule are also available for viewing.