San Mateo County Second Unit Ordinance Update
UPDATED Tuesday, April 18, 2017
San Mateo County Second Unit Ordinance Update and Proposed Amendment to the Implementation Plan of the County’s Local Coastal Program
On January 10, 2017, the San Mateo County Board of Supervisors adopted an update to the County’s Second Unit Regulations, Chapter 22.5 of the Zoning Regulations. See the new regulations (also attached below).
Second units, also known as “accessory dwelling units,” (or “granny units,” “in-law units,” and various other names) are smaller units built on the same property as, or attached to, an existing primary residence. The County of San Mateo regulates the production of second units in the unincorporated areas of the County only (those areas that are not in the jurisdiction of incorporated cities), and the adopted changes to the second unit regulations imact only second units created in those unincorporated areas.
The purpose of this update is twofold:
- To make changes required by state law, specifically California Government Code 65852.2, as most recently amended by Senate Bill 1069 in 2016. State law requires local jurisdictions to amend their regulations regarding second units in specific ways, in order to facilitate the production of second units.
- To pursue the intent and direction of the County Board of Supervisors, as expressed through the County Housing Element, the recently endorsed Housing White Paper, and other policy statements, to prioritize and facilitate production of second units as a valuable source of additional and often more affordable housing that can help address the County’s housing affordability crisis.
Key changes to the ordinance include:
- Minor changes in the maximum allowed floor area of second units, from 1,500 to 1,200 square feet
- Slight reductions in required parking, and changes in how and where that parking may be provided
- Changes to the required setbacks for second units
- Limitations on the allowed height of second units
- A variety of other minor changes intended to comply with the most recent amendments to the California Government Code
The most significant change, required by state law, is to formalize the review and approval of those second units which comply entirely with zoning regulations as a non-discretionary approval, meaning that if the unit complies with applicable regulations, it will not be reviewed at a public hearing, will not be appealable, and will be reviewed as a simple permit that the County will not have the ability to deny. This formalizes the County’s current practice, which complies with these requirements.
A number of these changes are similarly formalizing policies and procedures that the County has been implementing, pursuant to the requirements of state law, but which had not previously been formally enacted.
The adopted regulations are now in effect in the non-Coastal areas of San Mateo County. However, because the updated regulations also address second units created in the County’s Coastal Zone, they constitute a proposed amendment to the Implementation Plan of the County’s Local Coastal Program, and will not take effect until certified by the California Coastal Commission. At the direction of the Board of Supervisors, the adopted regulations have been submitted to the Coastal Commission for review and certification, and will take effect once certification is complete. The timeline for the Coastal Commission’s review and action is uncertain.
The updated regulations, adopting ordinance, resolution directing submittal to the California Coastal Commission, and accompanying staff report are available here:
If you have any questions about the updated regulations, please contact:
455 County Center, 2nd Floor
Redwood City, CA 94063