What is base flood elevation (BFE)?
Base flood elevation (BFE) is the height floodwater is expected to reach in the 1% annual-chance flood, shown on FEMA's maps in AE, AH and VE zones.
In more detail
BFE is measured against a fixed survey datum, so it's compared with the elevation of a building's lowest floor, not with the ground.
Under the National Flood Insurance Program's minimum rules, new and substantially improved homes in high-risk zones must have the lowest floor at or above BFE. Many communities require one to three feet more, called freeboard. Commercial buildings can instead be floodproofed to that height.
An elevation certificate, completed by a surveyor or engineer, records a building's floor heights against BFE.
What it means when you buy
The gap between the lowest floor and BFE is the biggest single driver of flood insurance cost. A building below BFE can also be limited in how much you can renovate before it must be raised.
How the free flood check shows it
Where FEMA publishes a BFE, the free flood check compares it with the ground height at each building to estimate how deep the water would be.
Check the flood zone for an address, free
Enter any US address to see its FEMA flood zone and a map of the flood areas around it. Add your email to see which buildings sit in the flood zone and the risk numbers.