Free tool
Flood zone lookup by address
Enter a U.S. address to see its flood zone on FEMA’s flood risk map, whether it sits in the high-risk floodplain where lenders require flood insurance, the map panel’s effective date, the ground elevation, and how many flood insurance claims its ZIP code has had since 1978, ranked against the rest of the country.
Free, no sign-up. Uses FEMA’s National Flood Hazard Layer and flood insurance claims data, and USGS 3DEP elevation data (via Mapbox).
Not an official determination. This lookup reads FEMA’s public digital flood map at the point we find for the address. It isn’t an official flood zone determination: your lender orders its own, and recent map changes (such as a Letter of Map Amendment or Revision) or preliminary maps may not appear. A building can sit in a different zone than the point on its lot. Confirm on FEMA’s Flood Map Service Center before a purchase or insurance decision. Claim counts come from FEMA’s public flood insurance data, which has no addresses: they cover the whole ZIP code and insured buildings only, and say nothing about whether this particular house flooded. The national comparison divides each ZIP code’s claims by its number of homes (Census Bureau estimates) and ranks it against U.S. ZIP codes with at least 100 homes. If FEMA’s live service doesn’t respond, the lookup uses Terreflow’s copy of the same FEMA data and says so.
What the result means
- Zones A and V (A, AE, AH, AO, AR, A99, V, VE) are Special Flood Hazard Areas, which FEMA defines as “the area that will be inundated by the flood event having a 1-percent chance of being equaled or exceeded in any given year” (FEMA). In communities in the National Flood Insurance Program, flood insurance is mandatory there for government-backed mortgages.
- Shaded Zone X (B on older maps): FEMA’s “moderate flood hazard areas,” “between the limits of the base flood and the 0.2-percent-annual-chance (or 500-year) flood” (FEMA), or behind a levee.
- Zone X (C on older maps): FEMA’s “areas of minimal flood hazard” (FEMA), which FloodSmart says are “at a lower risk of flooding, though not entirely without risk” (FloodSmart). Local runoff can still flood a house here! In the 20 flood-prone counties we analyzed, one in three flood insurance claims came from moderate- and low-risk zones.
- Zone D: “Areas where flood risk has not been determined and no flood hazard analysis has been conducted.” As FloodSmart puts it, “‘undetermined risk’ doesn’t mean ‘no risk.’” (FloodSmart)
For more detail, read Is my house in a flood zone? Why Zone X can still flood.
How does a ZIP code’s flood claim history compare?
FEMA’s records list about 2.7 million National Flood Insurance Program claims from 1978 to 2026. A big ZIP code naturally has more claims than a small one, so the lookup divides each ZIP code’s claims by its number of homes and ranks it against the 30,078 U.S. ZIP codes with at least 100 homes.
| ZIP code rank | Flood insurance claims per 1,000 homes, 1978–2026 |
|---|---|
| Median ZIP code | 2 |
| Top 25% | More than 9 |
| Top 10% | More than 34 |
| Top 5% | More than 76 |
| Top 1% | More than 356 |
Flood claims are concentrated: 27% of these ZIP codes have no recorded claim at all, while the top 10% account for 76% of their claims. A high rank means the area has flooded often or widely enough to produce many insured losses. A low rank isn’t a clean bill of health: only buildings with flood insurance can file a claim, and the figure describes the whole ZIP code, not one house.
Terreflow analysis of FEMA’s OpenFEMA flood insurance claims (data as of September 8, 2026) and Census Bureau housing counts (American Community Survey 2020–2024). Claims with no ZIP code, about 2%, are left out.
What a flood zone can’t tell you
Floodplain maps show where rivers, lakes and the sea are expected to overflow. They don’t show where heavy rain runs downhill and collects, whether the house has flooded before, or how the lot is graded. The ZIP code’s claim history shows how often the area around it has flooded; for the house itself, see the guide below. The ground elevation above gives a first hint: a spot lower than most of the land around it can receive runoff from its neighbors.
- Has this house flooded before? How to check
- How to read a drainage map
- Terrain checklist before buying land
Sources
- FEMA, National Flood Hazard Layer (flood zones and FIRM panels)
- FEMA, OpenFEMA: NFIP Redacted Claims (v3) (flood insurance claims by ZIP code)
- U.S. Census Bureau, American Community Survey 2020–2024 5-year estimates, table B25001 (housing units by ZIP Code Tabulation Area)
- U.S. Geological Survey, 3D Elevation Program (3DEP), via Mapbox terrain tiles