The 100 year flood is a national standard for determining the 1% chance (1 out of 100) of a flood of such magnitude that would require the purchase of flood insurance. But just so you know, this magnitude of flood could occur in any given year. It is a base measurement for regulating development in a floodplain.

Base Flood Elevations are the high water marks for the 100 yr flood. They are measured in mean sea level (MSL) or depths above the natural ground. This is the means by which we set the home’s lowest floor or bottom of frame if it is a manufactured home in order to give it maximum protection from flooding. This number is a limiting factor for floodplain building—do not go below the BFE. The Regulatory Flood Elevation, or RFE is one foot above the BFE to further protect from flooding.