What flood zone is this address in? FEMA’s answer in plain English.

The problem

Flood maps answer the question, but they speak in codes

FEMA’s flood maps are the authority on flood risk in the United States, but reading one means finding the right map panel, decoding a zone letter like AE or VE, and working out whether a base flood elevation applies and which vertical datum it uses. For a question as ordinary as “is this house in a high-risk flood area,” that is a lot to decode before you get an answer.

What it answers

One US point, everything FEMA maps about it

• The FEMA flood zone — A, AE, AH, AO, A99, V, VE, X or D — explained in plain English.
• Whether the point is in a Special Flood Hazard Area: yes or no.
• The base flood elevation or flood depth, with its datum and unit, wherever FEMA maps one.
• The Flood Insurance Rate Map (FIRM) panel number and its effective date.
• Letters of Map Revision (LOMRs) and Letters of Map Amendment (LOMAs) touching the point.
• Floodway, the Limit of Moderate Wave Action (Coastal A Zone), levees, and U.S. Fish and Wildlife Service Coastal Barrier Resources System units.
• Pending and preliminary FEMA maps that may change the answer, the nearest high-risk zone, and the community name.
• A share link and a print view, plus links straight to FEMA’s Flood Map Service Center and an official FIRMette.

Launch Flood Zone Finder

How to read the result

High risk, moderate to low risk, and the base flood elevation

Special Flood Hazard Area (zones starting with A or V). These are FEMA’s high-risk areas: land with at least a 1% chance of flooding in any year, often called the “100-year flood.” V zones add coastal wave action. In communities that take part in the National Flood Insurance Program, flood insurance is mandatory for buildings in these areas that carry a federally backed mortgage.

Zone X. Moderate to low risk — outside the 1% annual-chance floodplain. Flood insurance is not federally required there, but floods still happen outside high-risk areas. Zone D means the flood risk has not been studied.

Base flood elevation (BFE). The height floodwater is expected to reach in the 1% annual-chance flood, measured against a vertical datum such as NAVD 88 or NGVD 29. Zones AE, AH and VE usually carry one; Zone AO carries a flood depth in feet instead. Comparing the BFE with a building’s elevation is what drives elevation certificates and insurance rating.

Watch it work

The four-minute walkthrough

Three real places, three different answers: a Miami high-risk zone with its base flood elevation, a coastal VE zone on the Outer Banks, and a Zone X town in New Hampshire.

Where the data comes from

FEMA flood maps, served live

Flood zones, base flood elevations, map panels and map letters come from FEMA’s National Flood Hazard Layer, read through Esri’s ArcGIS Living Atlas USA Flood Hazard Reduced Set and FEMA’s public NFHL map service. Coastal Barrier Resources System units come from the U.S. Fish and Wildlife Service Coastal Barrier Resources Act program mapper. Address search uses ArcGIS World Geocoding for US addresses; searches are not stored.

All Things Spatial is not affiliated with or endorsed by FEMA, the U.S. Fish and Wildlife Service or Esri. The flood maps are FEMA products, not All Things Spatial ones.

Before you rely on it

Information only

Flood Zone Finder is for information only. It is not an official flood zone determination for insurance or lending. For that, use FEMA’s Flood Map Service Center, or ask your lender or your community floodplain manager.