Zone A is a high-risk flood zone mapped without detailed study. Here is what that means. Paste an address below to see its FEMA flood zone, or a whole list to check them all at once.
Quick answer
Flood zone A is a high-risk flood area: land with a 1% or greater chance of flooding each year (the "100-year floodplain"), mapped by approximate methods, so FEMA shows no base flood elevation. It is part of the Special Flood Hazard Area: flood insurance is required for mortgages from federally regulated or insured lenders, and new buildings must meet the community's floodplain rules, which in zone A often means working out a base flood elevation for the site first.
Step 1 of 2 · about a minute
Or paste one address per line
US addresses with a house number and a state or ZIP. Only the address is used for the check.
Because zone A was mapped without a detailed hydraulic study, there's no published flood height. Before building, communities usually ask for one from other sources, or from a study of the site, so the lowest floor can be set above it.
All of them are the 1% annual chance floodplain. AE (and the older A1 to A30) has base flood elevations from detailed study; AH is shallow ponding one to three feet deep; AO is shallow sheet flow on slopes, with depths shown instead of elevations; A99 is land a federal flood protection system under construction will protect; AR is behind a levee being restored.
As in every A zone, flood insurance is required with a mortgage from a federally regulated or insured lender. Since Risk Rating 2.0 the premium is set on the property's own risk. If the building is on ground above the actual flood level, a Letter of Map Amendment (LOMA) can remove it from the high-risk area.
A guide and a planning check, not an official flood zone determination: a lender's determination, or FEMA's own map, is the official answer for a single property.
What does flood zone A mean?
A high-risk flood area with a 1% or greater annual chance of flooding, mapped by approximate methods, so no base flood elevation is shown.
Is zone A worse than zone AE?
Not riskier: both are the 100-year floodplain. Zone A is less precisely mapped, with no base flood elevation, which can make building and insurance paperwork harder.
Is flood insurance required in zone A?
Yes, for mortgages from federally regulated or insured lenders, as in every zone that starts with A or V.
What is zone A99?
Land a federal flood protection system will protect once it is finished. It is still in the high-risk area, with no base flood elevations shown.
How do I check if an address is in zone A?
Enter it in the checker above: it shows the FEMA zone for the address from the National Flood Hazard Layer.