San Mateo County is undertaking the rezoning of multiple parcels in various areas of the County to allow higher-density multifamily development, in order to meet the County’s quantified housing need, as mandated by State law. This rezoning is part of the County’s updated Housing Element, adopted by the County Board of Supervisors on March 25, 2025.
What is Rezoning?
Zoning regulations establish the basic rules for what may be built on a parcel (property), including the kinds of uses (housing, retail, office, industrial, etc), the density or intensity of uses (housing units per acre, square feet allowed per acre), and standards for height, bulk, placement of structures, and other regulations. Rezoning is a change in the zoning regulations for a given parcel or area, to change allowed uses, intensities, and other standards.
Why Rezoning?
The proposed rezonings are required by State law, as part of the County’s updated Housing Element.
Under State law, all jurisdictions in California are required to have a Housing Element as part of their General Plan. The Housing Element must establish goals, policies and programs to meet the jurisdiction’s housing needs. Housing Elements must be periodically updated on a schedule established by State law, with processes and contents also established by State law. Updated Housing Elements must be submitted to the California Department of Housing and Community Development (HCD) for a determination of compliance with State law.
The County’s updated Housing Element is here. More information on the County’s Housing Element update process is here.
A crucial component of the Housing Element is demonstration that the County can meet its State-mandated share of regional housing need, known as its Regional Housing Needs Allocation (RHNA). The County’s RHNA is its share of the Bay Area’s total housing need over the next 8 years, in total and by income level, as determined by the State and the Association of Bay Area Governments. San Mateo County’s RHNA is shown below.
| Income Category | Housing Units |
|---|---|
| Very Low | 811 |
| Low | 468 |
| Moderate | 433 |
| Above Moderate | 1,121 |
| Total | 2833 |
The Housing Element must assess the development potential of every parcel in the County available for residential development. If the County has insufficient developable sites to meet its RHNA, it must identify sites that will be rezoned for higher density residential development in order to generate additional development capacity.
| Income Category | RHNA | Capacity (Units) | Surplus/Deficit |
|---|---|---|---|
|
Very Low |
811 | 457 | (354) |
| Low | 468 | 356 | (112) |
| Moderate | 433 | 254 | (179) |
| Above Moderate | 1,121 | 801 | (319) |
| Total | 2,833 | 1,870 | (963) |
During the Housing Element update, the County assessed the development potential of every available parcel in the County. The County’s current residential development capacity is almost 1,000 units short of the number required to meet its share of residential development over the next 8 years.
Because the County does not currently have sufficient sites for residential development, it is required by law to rezone additional sites for higher-density multifamily development. By law, these sites must also be distributed across the County in areas of differing geography, community type, community income level, and other factors to ensure that higher-density housing and lower-income housing are not overly concentrated in any given area or community. The proposed rezonings must also be submitted to the California Department of Housing and Community Development for approval.
The County has identified sites for rezoning throughout the unincorporated County, described in the Housing Element Rezoning Program incorporated in the adopted Housing Element as Program 11.2, addressing the County’s legal obligation to meet its RHNA. This rezoning program has been approved by HCD.
Environmental Review
Changes to zoning in general are subject to the California Environmental Quality Act, which requires assessment of a project’s impact on the environment. The Rezoning Program will include a full Environmental Impact Report (EIR), which will assess all possible environmental impacts of the rezonings, and provide mitigation for any potential impacts.
Public Process
Creation and adoption of the new zoning designations will involve public outreach, meetings, and public hearings at the Planning Commission and Board of Supervisors. All zoning amendments must ultimately adopted by the Board of Supervisors. For parcels in El Granada, on the County’s coast, the amendments must also be submitted to the California Coastal Commission for review and approval. Opportunities to participate in the process will be listed on this website, and notifications will be distributed by email, social media, and other methods.
In addition, any comments or questions may be submitted at the contact information listed below.
Important Notes
These rezonings are required by State law. The County cannot choose not to meet its RHNA obligations.
Rezoning changes the rules for what is allowed on a parcel. However, rezoning is not a development project. There is no development proposed on any of the parcels in the rezoning program.
No development on any rezoning parcel is currently proposed. The County is not proposing current or future development on any of the parcels in the zoning program. The parcels are not owned by the County, and the County is not a housing developer. Future residential development in the County will depend on private market forces, housing supply and demand, and various other factors
Project Timeline
| Project Phase | Projected Timeline |
|---|---|
| Project Kickoff | July 2025 |
| Information Gathering, Data Collection, Analysis | September 2025 – December 2025 |
| Outreach, Public Meetings | September 2025 – February 2026 |
|
Draft Amendments |
October 2025 – February 2026 |
|
Environmental Review |
September 2025 – July 2026 |
|
Final Amendments |
May/June 2026 |
|
Planning Commission Hearings |
March 2026 – July 2026 |
|
Board of Supervisors Hearings |
March 2026 – July 2026 |
|
Coastal Commission Submittal and Certification (coastal parcels) |
July 2026 – Dec 2026 |
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