Glossary

Flood zone

A map designation, such as Zone AE, VE or X, that classifies a property's flood risk and helps decide whether a lender will require flood insurance.

Also called: FEMA flood zone, flood hazard zone, zone AE, zone X

A flood zone is a label on FEMA's flood maps that sorts land by flood risk. Zones beginning with A or V are high-risk: Zone A and AE have a 1% annual chance of flooding, Zone AE also shows a base flood elevation, and Zones V and VE are coastal areas with added wave hazard. Shaded Zone X (older maps: Zone B) marks moderate risk between the 1% and 0.2% annual-chance floods. Unshaded Zone X (older maps: Zone C) is minimal hazard.

A 1% annual chance is often called a "100-year flood," which suggests a schedule. It is better read as a probability: FEMA puts the chance of at least one such flood during a 30-year mortgage at about 26%.

Zone X does not mean zero risk. FEMA cautions that low risk is not no risk, and flood damage does happen outside high-risk zones. Maps also lag reality as development and weather patterns change. Under Risk Rating 2.0, the NFIP no longer prices a policy mainly by zone, but the zone still decides whether a lender must require coverage. Look up your address on FEMA's Flood Map Service Center, and read flood zones and FEMA flood maps explained and do you need flood insurance outside a high-risk zone before deciding to skip coverage.

Last reviewed October 10, 2026

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Related terms

Special flood hazard area (SFHA) The land FEMA maps as having at least a 1% chance of flooding in any year, where lenders must require flood insurance on federally backed mortgages. Flood insurance rate map (FIRM) FEMA's official map of a community showing flood zones, base flood elevations and floodways, which lenders use to decide whether flood insurance is required. Base flood elevation (BFE) The height, in feet above a standard reference level, that floodwater is expected to reach in a flood with a 1% chance of occurring in any year. National Flood Insurance Program (NFIP) The federal program, run by FEMA since 1968, that makes flood insurance available to owners and renters in communities that adopt floodplain management rules. Risk Rating 2.0 FEMA's current method of pricing NFIP flood policies by each home's own flood risk and rebuilding cost rather than mainly by flood zone and elevation. Elevation certificate A form completed by a licensed surveyor, engineer or architect that records a building's key elevations against the mapped base flood elevation.

Related guides

Insuring a coastal home: wind, flood and where to find coverage Coastal owners often assemble coverage from several sources: a homeowners policy, a flood policy and sometimes a state wind pool. How the pieces fit and cost. Do you need flood insurance outside a high-risk zone? Federal law requires flood insurance only in high-risk zones, yet FEMA says nearly a third of NFIP claims come from outside them. How to decide and when to buy. Elevating a home and other flood mitigation How elevation, flood openings, raised equipment, floodproofing and buyouts work, what each does to flood insurance premiums, and where the money comes from. Flood zones and FEMA flood maps explained What the A, V, X and D flood zones mean, how to look up your address on a FEMA map, what a zone changes for your lender, and how to contest one with a LOMA. Insurance cost disclosure in home sales What sellers must and must not tell buyers about claims, flood history and insurability, why no law makes them disclose premiums, and how buyers find out. Risk Rating 2.0: how NFIP prices flood insurance now Since 2021 FEMA prices NFIP flood policies by each property's own flood risk and rebuild cost, not by zone. What drives your rate, the 18% cap, how to lower it.