Definitions of FEMA Flood Zone Designations

Areas outside the 1-percent annual chance floodplain, areas of 1% annual chance sheet flow flooding where average depths are less than 1 foot, areas of 1% annual chance stream flooding where the contributing drainage area is less than 1 square mile, or areas protected from the 1% annual chance flood by levees. No Base Flood Elevations or depths are shown within this zone. Insurance purchase is not required in these zones.

 Areas with a 1% annual chance of flooding and a 26% chance of flooding over the life of a 30-year mortgage. Because detailed analysis are not performed for such areas; no depths or base flood elevations are shown within these zones 

Areas with a 1% annual chance of flooding and a 26% chance of flooding over the life of a 30-year mortgage. In most instances, base flood elevations derived from detailed analysis are shown at selected intervals within these zones.

Areas with a 1% annual chance of shallow flooding, usually in the form of a pond, with an average depth ranging from 1 to 3 feet. These areas have a 26% chance of flooding over the life of a 30-year mortgage. Base flood elevations derived from detailed analysis are shown at selected intervals within these zones.

 River or stream flood  hazard areas and areas with a 1% or greater chance of shallow flooding  each year, usually in the form of sheet flow, with an average depth  ranging from 1 to 3 feet. These areas have a 26% chance of flooding over  the life of a 30-year mortgage. Average flood depths derived from  detailed analysis are shown within these zones.  

 Areas with a  temporarily increased flood risk due to the building or restoration of a  flood control system (such as a levee or a dam). Mandatory flood  insurance purchase requirements will apply, but rates will not exceed  the rates for unnumbered A zones if the structure is built or restored  in compliance with Zone AR floodplain management regulations.  

 Areas with a 1% annual  chance of flooding that will be protected by a Federal flood control  system where construction has reached specified legal requirements. No  depths or base flood elevations are shown within these zones.  

Coastal areas with a 1% or greater chance of flooding and an additional hazard associated with storm waves. These areas have a 26% chance of flooding over the life of a 30-year mortgage. No base flood elevations are shown within these zones.

Coastal areas with a 1% or greater chance of flooding and an additional hazard associated with storm waves. These areas have a 26% chance of flooding over the life of a 30-year mortgage. Base flood elevations derived from detailed analysis are shown at selected intervals within these zones.

Areas with possible but undetermined flood hazards. No flood hazard analysis has been conducted. Flood insurance rates are commensurate with the uncertainty of the flood risk.