Palo Alto, California Flood Zones
Palo Alto faces dual flood threats from San Francisquito Creek and San Francisco Bay shoreline inundation. The 1998 San Francisquito Creek flood damaged hundreds of homes and prompted major flood control investments, while rising bay waters increasingly threaten low-lying neighborhoods near the coast.
FEMA Flood Risk Profile: Santa Clara 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
Very HighEst. annual loss: $720.2M
Coastal Flood Risk
Relatively HighEst. annual loss: $6.7M
Source: FEMA National Risk Index, county-level assessment. Individual property risk may vary.
Federal Flood Disaster History: Santa Clara County
Santa Clara County has been included in 7 federal flood-related disaster declarations.
...and 1 earlier declaration since 1982.
These declarations affected communities across Santa Clara County, including Palo Alto.
Source: OpenFEMA Disaster Declarations Summaries API. Data sourced February 2026.
NFIP Flood Insurance Claims: Santa Clara County
Properties in Santa Clara County have filed 1,630 NFIP flood insurance claims totaling $24.5M in payouts since 1978. The average claim payout is $15K.
Highest-Claim Years
1998
536 claims - $9.5M
1995
196 claims - $1.4M
2017
188 claims - $7.4M
Claims by Flood Zone
Zone AO
398
Zone A
381
Zone AE
265
Zone X
181
Zone AH
120
Source: OpenFEMA NFIP Claims API. Data sourced February 2026.
Common Flood Zones in Palo Alto
Properties in Palo Alto, CA are commonly designated in these FEMA flood zones:
What Your Flood Zone Means in Palo Alto
Palo Alto faces multiple inland flood threats, including riverine flooding from nearby waterways and flash flooding from intense rainfall overwhelming urban drainage systems. Properties near river corridors face the highest risk, but stormwater backup can affect neighborhoods well outside the mapped floodplain. The most common FEMA flood zone designations in Palo Alto are Zone AE, Zone AO, Zone X. FEMA's National Risk Index estimates the county's annual expected loss from inland flooding at over $720.2M. Palo Alto has Zone AO areas subject to sheet-flow flooding, where shallow water spreads across broad, flat terrain rather than channeling through waterways.
With both riverine and urban stormwater flood risk, insurance costs in Palo Alto depend heavily on a property's elevation relative to nearby waterways and the local drainage infrastructure. FEMA's Risk Rating 2.0 prices in multiple inland flood sources rather than relying on the flood zone line alone. 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 zone boundaries in Palo Alto can shift when FEMA updates its Flood Insurance Studies or when upstream development changes how water moves through the watershed. New stormwater infrastructure or dam modifications can also trigger map revisions. Use our free lookup tool to check the current flood zone for any Palo Alto address.
Flood Insurance Discount: Palo Alto
Palo Alto 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 6
SFHA Premium Discount
20% off
CRS classes range from 1 (best) to 10 (no discount). Palo Alto's Class 6 rating means NFIP policyholders in the SFHA can receive up to a 20% discount on their flood insurance premiums. Properties outside the SFHA may receive a 10% discount.
Source: FEMA Community Rating System, October 2025. Discounts apply to NFIP policies only.
Check Your Palo Alto Address
Enter any Palo Alto, CA address to instantly see its FEMA flood zone, risk level, and whether flood insurance is required.
Free Flood Zone LookupPalo Alto, CA Flood Zone FAQ
What flood zones are in Palo Alto, CA?
The most common FEMA flood zones in Palo Alto are Zone AE, Zone AO, 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 Palo Alto?
If your Palo Alto 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 about 25% of all NFIP flood claims come from Zone X properties.
How do I check my flood zone in Palo Alto?
Enter your Palo Alto 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 Palo Alto offer flood insurance discounts?
Yes. Palo Alto participates in FEMA's Community Rating System (CRS) with a Class 6 rating, qualifying residents in the Special Flood Hazard Area for up to a 20% discount on NFIP flood insurance premiums. Properties outside the SFHA may receive a 10% discount.
Has Palo Alto experienced major flooding events?
Santa Clara County, where Palo Alto is located, has been part of 7 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 Palo Alto?
Santa Clara County has recorded 1,630 NFIP flood insurance claims totaling $24.5M in payouts since 1978. The year with the most claims was 1998, with 536 claims and $9.5M in payouts. These figures cover all NFIP claims in the county, including Palo Alto.
Sources
This page summarizes information from FEMA and other official resources in plain language. For full technical details, see the links below.
- FEMA National Flood Hazard LayerDirect Source
The NFHL is the source of all flood zone data shown on this page.
- FEMA Map Service Center — Search by AddressDirect Source
Look up any address to view FIRM panels, FIS reports, and LOMCs.
- NFHL Data and Map StatusTopic Page
View NFHL coverage and data freshness by state and community.
- FEMA National Risk Index — Data ResourcesDirect Source
County-level risk scores for inland flooding, coastal flooding, and hurricane used in the Flood Risk Profile.
- OpenFEMA Disaster Declarations Summaries API v2Direct Source
Federal disaster declarations filtered for flood-related incident types (Flood, Hurricane, Severe Storm, Coastal Storm).
- OpenFEMA FIMA NFIP Claims API v2Direct Source
Historical NFIP flood insurance claims since 1978, aggregated by county and state. Includes claim counts, payouts, and flood zone breakdowns.
Sources last verified: February 2026