Areas of moderate or minimal hazard are studied based on the principal source of flood in the area. However, buildings within these zones could also be flooded by severe, concentrated rainfall coupled with inadequate drainage systems. Local storm water drainage systems are not normally accounted for in a community’s flood insurance study. The failure of a local drainage system can create areas of high flood risk within these zones. Flood insurance is available in participating communities, but is not required by regulation in these zones. Nearly 25% of all flood claims are from structures in these zones.
| Zone | Description |
| B, X (shaded) | Moderate-risk areas within the 0.2-annual-percent-chance floodplain; areas of 1-percent-annual-chance flooding where average depths are less than 1 foot; areas of 1-percent-annual-chance flooding where the contributing drainage area is less than 1 square mile and; areas protected from 1-percent-annual-chance flooding by a levee. No BFEs or base flood depths are shown in these areas. (Zone X – shaded – is used on new and revised maps in place of Zone B.) |
| C, X (unshaded) | Minimal-risk areas outside 1-percent- and 2-percent-annual-chance floodplains. No BFEs or base flood depths are shown. (Zone X – unshaded – is used on new and revised maps in place of Zone C.) |
| *Source: Chatham County-Savannah Metropolitan Planning Commission | |