The Federal Emergency Management Agency produces and distributes all official flood plain maps, which are available on the FEMA.gov website as well as from most insurance agencies and county planning commissions. The FEMA website allows users to search by their address for local flood plain maps at no charge.
Most areas of the United States have been mapped by FEMA as of April 2015; however, some areas have not. Homeowners and business owners should check for flood plain map updates at least annually when their insurance policies are up for renewal. A change in a property's status could result in significant premium increases or potentially insufficient policy coverage.