Where it is unclear from the FEMA floodplain maps whether your property is, or is not in the floodplain, you can use our geographic information system (GIS) to look up your property and select the layer entitled “Floodplain Mapping Effective 9-26-20” on the right-hand side of the page to overlay the floodplain onto your property. The blue hatched areas represent areas that have a one-percent chance of flooding in any given year (formerly known as the 100-year floodplain), which are the areas used to determine whether flood insurance is required.