"The NFIP was established by the National Flood Insurance Act of 1968 (NFIA, 42 U.S.C. §4001 et seq.), and was most recently reauthorized to November 30, 2018, through a series of short-term reauthorizations. The general purpose of the NFIP is both to offer primary flood insurance to properties with significant flood risk, and to reduce flood risk through the adoption of floodplain management standards. Communities volunteer to participate in the NFIP in order to have access to federal flood insurance, and in return are required to adopt minimum standards. FEMA manages a process, called Risk MAP, to produce Flood Insurance Rate Maps (FIRMs). Depicted on FIRMs are Special Flood Hazard Areas (SFHAs), which is the area exposed to a 1% or greater risk of annual flooding. FIRMs vary in age across the country, and are updated on a prioritized basis. The Risk MAP process provides extensive outreach and appeal opportunities for communities. Updating a community's FIRMs can take three to five years or more. Participating communities must adopt a flood map and enact minimum floodplain standards to regulate development in the SFHA. FEMA encourages communities to enhance their floodplain standards by offering reduced premium rates through the Community Rating System (CRS). FEMA also manages a Flood Mitigation Assistance (FMA) grant program using NFIP revenues to further reduce comprehensive flood risk."
CRS Report for Congress, R44593
Congressional Research Service: https://crsreports.congress.gov/