San Carlos, California Flood Zones
Last updated: March 2026
San Carlos faces flooding from Pulgas Creek, Cordilleras Creek, and tidal influence from San Francisco Bay. Heavy atmospheric river storms produce rapid hillside runoff that can overwhelm creek channels flowing through residential neighborhoods toward the bay.
San Mateo County has recorded 1,109 NFIP flood insurance claims since 1978, totaling $20.0M in payouts. Explore the full NFIP claims data by state and county to see how this area compares nationally.
FEMA Region
Region 9
NFIP Policies
4,896
San Mateo County
Avg. Premium
$1,291/yr
San Mateo County
FEMA Flood Risk Profile: San Mateo County
Based on FEMA's National Risk Index, which evaluates flood risk at the county level using historical loss data, exposure, and vulnerability.
Inland Flood Risk
Relatively HighEst. annual loss: $212.3M
Coastal Flood Risk
Relatively HighEst. annual loss: $8.7M
Source: FEMA National Risk Index, county-level assessment. Individual property risk may vary.
Federal Flood Disaster History: San Mateo County
San Mateo County has been included in 8 federal flood-related disaster declarations.
...and 2 earlier declarations since 1982.
These declarations affected communities across San Mateo County, including San Carlos.
Source: OpenFEMA Disaster Declarations Summaries API. Data sourced February 2026.
NFIP Flood Insurance Claims: San Mateo County
Properties in San Mateo County have filed 1,109 NFIP flood insurance claims totaling $20.0M in payouts since 1978. The average claim payout is $18K.
Highest-Claim Years
1998
236 claims - $3.8M
1982
156 claims - $906K
2022
97 claims - $6.0M
Claims by Flood Zone
Source: OpenFEMA NFIP Claims API. Data sourced March 2026. See national claims data.
Flood Insurance Coverage: San Mateo County
An estimated 2% of households in San Mateo County carry NFIP flood insurance. This county has elevated flood risk but very low insurance coverage, indicating a significant protection gap.
Penetration Rate
2%
Claims Ratio
1 in 4
policies have filed a claim
Avg. Claim Payout
$18,050
Derived from FEMA NRI population data and OpenFEMA NFIP policy/claims records.
Repetitive Loss Properties: San Mateo County
San Mateo County has 48 properties with multiple flood losses, including 6 severe repetitive loss properties.
Multiple Loss
48
Severe Rep. Loss
6
Mitigated
0
By Flood Zone
Source: OpenFEMA NFIP Multiple Loss Properties. Data sourced March 2026.
Recorded Flood Events: SAN MATEO County
NOAA has recorded 95 flood events in SAN MATEO County since 1996, causing $10.9M in damage and 1 death.
Costliest Events
Events by Type
Source: NOAA Storm Events Database, 1996-2026. Data sourced March 2026.
Flood Mitigation: San Mateo County
FEMA has funded mitigation for 774 properties in San Mateo County, investing $2.6M in flood risk reduction.
By Action Type
Source: OpenFEMA Hazard Mitigation Assistance. Data sourced March 2026.
What Your Flood Zone Means in San Carlos
San Carlos faces a combination of coastal and inland flood risks. Storm surge from hurricanes and tropical storms pushes seawater inland, while heavy rainfall simultaneously overwhelms rivers, bayous, and drainage infrastructure. This dual threat means flooding can come from multiple directions at once. The most common FEMA flood zone designations in San Carlos are Zone AE, Zone X. FEMA's National Risk Index estimates the county's annual expected loss from inland flooding at over $212.3M.
Combined coastal and inland flood exposure in San Carlos means properties may face higher premiums than areas with only one flood source. FEMA's Risk Rating 2.0 accounts for multiple flood sources, including coastal surge distance, river proximity, and rainfall-driven flooding. If your property is in a Special Flood Hazard Area (SFHA) and you have a federally regulated or government-backed mortgage, federal law generally requires your lender to ensure you carry flood insurance.
Flood maps in areas with combined coastal and inland risk are among the most complex in the FEMA system. Major storms often trigger FEMA restudies that can significantly shift zone boundaries. Letters of Map Revision (LOMR) after hurricanes may expand SFHA coverage as new storm data is incorporated. Use our free lookup tool to check the current flood zone for any San Carlos address.
Flood Insurance Discount: San Carlos
San Carlos participates in FEMA's Community Rating System (CRS), a voluntary program that rewards communities for flood mitigation efforts beyond minimum NFIP requirements. Residents in the Special Flood Hazard Area may qualify for reduced flood insurance premiums.
CRS Class
Class 9
SFHA Premium Discount
5% off
CRS classes range from 1 (best) to 10 (no discount). San Carlos's Class 9 rating means NFIP policyholders in the SFHA can receive up to a 5% discount on their flood insurance premiums. Properties outside the SFHA may receive a 5% discount.
Source: FEMA Community Rating System, October 2025. Discounts apply to NFIP policies only.
San Carlos, CA Flood Zone FAQ
What flood zones are in San Carlos, CA?
The most common FEMA flood zones in San Carlos are Zone AE, Zone X. Properties in these high-risk zones (SFHA) may require flood insurance with a federally regulated or government-backed mortgage.
Is flood insurance required in San Carlos?
If your San Carlos property is in a Special Flood Hazard Area (SFHA) and you have a federally regulated or government-backed mortgage, federal law generally requires your lender to ensure you carry flood insurance. Properties in Zone X are not federally required to carry flood insurance, though coverage is still recommended since over 40% of all NFIP flood claims come from Zone X properties.
How do I check my flood zone in San Carlos?
Enter your San Carlos address in the search tool above for an instant flood zone determination. Results include your FEMA flood zone, SFHA status, base flood elevation (if available), and FIRM panel information, pulled directly from FEMA's National Flood Hazard Layer.
Does San Carlos offer flood insurance discounts?
Yes. San Carlos participates in FEMA's Community Rating System (CRS) with a Class 9 rating, qualifying residents in the Special Flood Hazard Area for up to a 5% discount on NFIP flood insurance premiums. Properties outside the SFHA may receive a 5% discount.
Has San Carlos experienced major flooding events?
San Mateo County, where San Carlos is located, has been part of 8 federal disaster declarations for flooding, hurricanes, or severe storms. The most recent was Severe Winter Storms, Flooding, Landslides, and Mudslides in 2023. Federal disaster declarations are issued when flooding overwhelms local resources and triggers FEMA assistance programs.
How many flood insurance claims have been filed in San Carlos?
San Mateo County has recorded 1,109 NFIP flood insurance claims totaling $20.0M in payouts since 1978. The year with the most claims was 1998, with 236 claims and $3.8M in payouts. These figures cover all NFIP claims in the county, including San Carlos.
How many flood insurance policies are active in San Carlos?
San Mateo County currently has 4,896 active NFIP flood insurance policies with an average annual premium of $1,291. The most policies are in Zone AE (2,379 policies). These figures cover all active NFIP policies in the county.
How many San Carlos properties have flooded repeatedly?
San Mateo County has 48 properties with multiple flood losses on record, including 6 severe repetitive loss properties. These are properties that have experienced four or more NFIP claims of $5,000+ or two claims exceeding the building value.
Can my San Carlos property be removed from a high-risk flood zone?
Yes, if your property's natural ground elevation is above the Base Flood Elevation and FEMA inadvertently mapped it in a high-risk zone, you can apply for a Letter of Map Amendment (LOMA). A successful LOMA removes the property from the Special Flood Hazard Area, generally eliminating the federal mandatory flood insurance requirement. You will need an elevation certificate from a licensed surveyor. If a property was raised above the BFE with fill material, the process is a LOMR-F rather than a LOMA.
What is Base Flood Elevation in San Carlos?
Base Flood Elevation (BFE) is the predicted height of floodwaters during a 1% annual chance (100-year) flood, shown on FEMA maps as an elevation number in feet above sea level. In San Carlos's Zone AE areas, BFE lines appear on the FIRM as wavy contours labeled with elevation values. Properties with a lowest floor at or above the BFE typically qualify for significantly lower NFIP flood insurance premiums.
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Disclaimer: Flood risk data on this page is sourced from FEMA datasets including the National Risk Index, NFIP claims and policy records, disaster declarations, and the Community Rating System. These datasets were last extracted on March 2026 and may not reflect the most recent changes. This page is for informational purposes only and is not a certified flood zone determination. Always verify current flood zone status through FEMA or a licensed determination provider before making property, insurance, or lending decisions.