The mission of Federal Emergency Management Agency (FEMA) is to support our citizens and first responders to ensure that as a nation we work together to build, sustain and improve our capability to prepare for, protect against, respond to, recover from and mitigate all hazards.

Robert T. Stafford Disaster Relief and Emergency Assistance Act, Public Law 100-707, signed into law November 23, 1988; amended the Disaster Relief Act of 1974, Public Law 93-288. It created the system in place today by which a presidential disaster declaration of an emergency triggers financial and physical assistance through FEMA.  The Act gives FEMA the responsibility for coordinating government-wide relief efforts. It is designed to bring an orderly and systemic means of federal natural disaster assistance for state and local governments in carrying out their responsibilities to aid citizens.

Congress' intention was to encourage states and localities to develop comprehensive disaster preparedness plans, prepare for better intergovernmental coordination in the face of a disaster, encourage the use of insurance coverage, and provide federal assistance programs for losses due to a disaster.  For more information, go to or contact the Federal Emergency Management Agency, Region IX at (202) 646-2500. 


A Flood Insurance Rate Map (FIRM) is the official map of a community on which FEMA has delineated both the special hazard areas and the risk premium zones applicable to the community.

The County can determine the relationship of a particular property to the floodplain including:  (1) whether the property is located within the Special Flood Hazard Area; (2) Flood Insurance Rate Map (FIRM) Zone for property; (3) Base Flood Elevation for property, if available; and (4) whether the property is located within the Floodway.  The County also maintains elevation certificates for review, if available.  For further information or assistance, contact San Mateo County Planning and Building Department at 650/599-7310 or 650/599-7311.

Find the Flood Zone for Your Property
  1. You will need the 9-digit APN (0XX-XXX-XX0) for the property.  If there is a structure on the property information might also be available via address.
  2. Go to the GIS Database.
  3. On the “Layers” tab, expand the “Hazards” entry (click on the sideways triangle). Expand the “FEMA” tab, and then check the box for “FEMA Flood Zones” and “FEMA FIRM Panels”.
  4. Select “Find parcels by APN” or “Find Parcels by Address” at the top left corner of the screen. Enter the APN (leaving out the hyphens) or Address in the appropriate box.  Click “Search”. 

  5. Click on your property on the map.

  6. The flood zone and description should appear in the white pop-up box. If it does not appear, click the left and right arrows on the pop up box (where it says 1 of X) to shift to the appropriate panel. 

  7. Use the arrows of the pop-up box to shif to the FEMA FIRM Panel info. It will give the panel number, effective date, and option to download the FIRM Panel if available.

Find Your Flood Zone »

Hard-copy FEMA FIRM Maps that contain more detailed information specific to each panel area (i.e., base flood elevations) are available for viewing at the Planning Counter. You can also visit FEMA’s Flood Mapping Portal for more information.