FEMA draws a Flood Insurance Rate Map (FIRM) for each county and divides it into zones. The zone answers one question: how likely is this ground to flood in a given year.
- Zones A, AE, AH, AO, AR and A99 are the 1%-annual-chance floodplain, often called the 100-year floodplain. FEMA calls this a Special Flood Hazard Area. AE publishes a base flood elevation; plain A does not.
- Zones V and VE are the same 1% chance plus breaking waves of three feet or more. They carry stricter construction standards and the highest premiums. On the Mississippi coast this is common within a few blocks of the beach.
- Shaded X is the 0.2%-annual-chance (500-year) floodplain. Real exposure, no federal requirement.
- Unshaded X is minimal hazard. Most of Madison and Rankin counties away from the Pearl River and the Ross Barnett Reservoir sits here.
- Zone D means no study has been done. Unknown, not low.
Two things surprise buyers. First, the zone decides whether flood insurance is required, not what it costs — under Risk Rating 2.0, NFIP pricing comes from the building itself: distance to water, foundation, first-floor height, replacement cost. Second, maps change. A property can be mapped into a high-risk zone mid-loan, and a Letter of Map Amendment can take an individual structure back out of one.
Whatever the map says, a standard homeowners policy does not cover flood anywhere in Mississippi. Flood is always a separate policy.