Portsmouth, NH Flood Zone Lookup
Last updated: March 2026
Portsmouth faces coastal flooding from Atlantic storm surge and rising sea levels along its historic waterfront. Tidal flooding is an increasing concern in the low-lying downtown and port areas.
Rockingham County has recorded 2,164 NFIP flood insurance claims since 1978, totaling $30.3M in payouts. Explore the full NFIP claims data by state and county to see how this area compares nationally.
FEMA Region
Region 1
NFIP Policies
4,269
Rockingham County
Avg. Premium
$987/yr
Rockingham County
FEMA Flood Risk Profile: Rockingham 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 ModerateEst. annual loss: $54.0M
Coastal Flood Risk
Relatively HighEst. annual loss: $12.1M
Hurricane Risk
Relatively ModerateEst. annual loss: $5.0M
Source: FEMA National Risk Index, county-level assessment. Individual property risk may vary.
Federal Flood Disaster History: Rockingham County
Rockingham County has been included in 13 federal flood-related disaster declarations.
...and 5 earlier declarations since 1972.
These declarations affected communities across Rockingham County, including Portsmouth.
Source: OpenFEMA Disaster Declarations Summaries API. Data sourced February 2026.
NFIP Flood Insurance Claims: Rockingham County
Properties in Rockingham County have filed 2,164 NFIP flood insurance claims totaling $30.3M in payouts since 1978. The average claim payout is $14K.
Highest-Claim Years
2006
265 claims - $5.3M
1991
257 claims - $1.8M
2024
251 claims - $10.2M
Claims by Flood Zone
Source: OpenFEMA NFIP Claims API. Data sourced March 2026. See national claims data.
Flood Insurance Coverage: Rockingham County
Only roughly 1 in 29 households in Rockingham County carries NFIP flood insurance (3% of estimated households). With 39 recorded flood events and $16.9M in damage, most flood losses in this county are likely uninsured.
Penetration Rate
3%
roughly 1 in 29 households
Historical Claims Ratio
1 in 2
2,164 claims over 45+ years across 4,269 current policies
Avg. Claim Payout
$14,013
Per claim, county-wide since 1978
Historically, Rockingham County has averaged 1 claim for every 2 active policies (since 1978). This compares cumulative claims against today's policy count and does not predict future claim likelihood.
Coverage data: NFIP policies as of March 2026, claims since 1978 (March 2026), population from FEMA NRI. All figures are county-wide and include Portsmouth.
What Your Flood Zone Means in Portsmouth
Portsmouth is primarily at risk from coastal flooding, including hurricane storm surge, tidal flooding, and wave action. Coastal storms can push seawater inland with little warning, and properties in VE (Velocity) zones face the most severe exposure to breaking waves. The most common FEMA flood zone designations in Portsmouth are Zone AE, Zone VE, Zone X. FEMA's National Risk Index estimates the county's annual expected loss from inland flooding at over $54.0M. Properties in Portsmouth's VE zones face additional wave action risk beyond still-water flooding, which typically results in higher insurance premiums and stricter building requirements.
Coastal flood insurance premiums in Portsmouth are typically higher than inland areas due to the destructive force of storm surge and wave action. Properties in VE zones face the highest premiums because wave damage compounds the risk beyond still-water 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.
Coastal flood maps are among the most frequently updated in the FEMA system, as shoreline erosion and new storm surge modeling refine the boundaries. Letters of Map Revision (LOMR) may shift VE and AE zone boundaries after major storms or updated coastal studies. Use our free lookup tool to check the current flood zone for any Portsmouth address.
Repetitive Loss Properties: Rockingham County
Rockingham County has 194 properties with multiple flood insurance losses, including 19 severe repetitive loss properties. 4 properties have received FEMA mitigation funding. Severe repetitive loss is a subset of multiple loss, not a separate count. Data sourced March 2026.
Multiple Loss
194
2+ claims within 10 years
Severe Repetitive Loss
19
4+ claims or 2 exceeding value
Mitigated
4
Received FEMA mitigation
By Flood Zone
Zone data available for 185 of 194 properties.
Source: OpenFEMA NFIP Multiple Loss Properties. Data sourced March 2026.
Recorded Flood Events: Rockingham County
NOAA has recorded 39 flood events in Rockingham County since 1996, causing $16.9M in damage.
Costliest Events
Events by Type
Source: NOAA Storm Events Database, 1996-2026. Data sourced March 2026.
Flood Mitigation: Rockingham County
FEMA has funded mitigation for 75 properties in Rockingham County, investing $0 in flood risk reduction. Common mitigation actions include acquisition (buying and demolishing flood-prone structures), elevation (raising buildings above flood level), and safe rooms (wind/storm shelters for tornado and hurricane protection).
By Action Type
Source: OpenFEMA Hazard Mitigation Assistance. Data sourced March 2026.
Portsmouth, NH Flood Zone FAQ
What flood zones are in Portsmouth, NH?
The most common FEMA flood zones in Portsmouth are Zone AE, Zone VE, 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 Portsmouth?
If your Portsmouth 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 Portsmouth?
Enter your Portsmouth 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.
What type of flooding affects Portsmouth?
Portsmouth is primarily affected by coastal flooding including storm surge and wave action. The most common FEMA flood zone designations are Zone AE, Zone VE, Zone X. Use the free lookup tool above to check the specific flood zone for any Portsmouth address.
Has Portsmouth experienced major flooding events?
Rockingham County, where Portsmouth is located, has been part of 13 federal disaster declarations for flooding, hurricanes, or severe storms. The most recent was Severe Storms and Flooding 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 Portsmouth?
Rockingham County has recorded 2,164 NFIP flood insurance claims totaling $30.3M in payouts since 1978. The year with the most claims was 2006, with 265 claims and $5.3M in payouts. These figures cover all NFIP claims in the county, including Portsmouth.
How many flood insurance policies are active in Portsmouth?
Rockingham County currently has 4,269 active NFIP flood insurance policies with an average annual premium of $987. The most policies are in Zone AE (2,420 policies). These figures cover all active NFIP policies in the county.
How many Portsmouth properties have flooded repeatedly?
Rockingham County has 194 properties with multiple flood losses on record, including 19 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 Portsmouth 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 Portsmouth?
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 Portsmouth's Zone AE and Zone VE 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.
Other New Hampshire Cities
Understanding Flood Zones
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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.