Portsmouth, New Hampshire Flood Zones

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.