PDFWAC 173-158-040
Regulatory area.
The minimum regulatory area for state and local flood plain management regulations shall be those areas subject to a base (one hundred year) flood and designated as special flood hazard areas on the most recent maps provided by the Federal Emergency Management Agency (FEMA) for the National Flood Insurance Program (NFIP). Best available information shall be used if these maps are not available or sufficient as determined by the Federal Emergency Management Agency.