Wet floodproofing measures are typically used to protect electrical, heating, ventilation and air conditioning (also known as HVAC), and utility components of a structure when flooding occurs.

Many of these mitigation measures involve elevating equipment above the expected flood levels.  FEMA has flood maps that indicate these anticipated levels, called Base Flood Elevations (BFE). 

The Base Flood Elevation (BFE)is the anticipated elevation above mean sea level that the “base flood” is expected to reach. 

The base flood is a flood having a one percent chance of being equaled or exceeded in any given year.

The NFIP uses the BFE to describe the minimum elevation to which new development in a flood hazard area must be regulated. 

Flood water can easily damage electrical system components including service panels, meters, switches, and outlets.

Even if they are inundated for only short periods, electrical system components usually have to be replaced.

Short circuits in flooded systems pose an increased potential for fire. Raising electrical system components helps avoid such problems.

It makes sense to raise all components of the electrical system, including wiring, above the base flood level identified on the NFIP's Flood Insurance Rate Map for the location.

Additional elevation of electrical components above the recommended level further reduces the risk.

Licensed contractors ensure that electrical system modifications are performed correctly and according to all applicable codes. (Illustration shows structure showing the 100 year flood level, previous electrical locations (below the 100 year flood level) and the new raised wiring: raised switch, raised outlets, raised meter, and raised service panel.)

HVAC equipment, such as furnaces and hot water heaters, can be damaged extensively if inundated by flood waters.

A good way to protect HVAC equipment is to locate it on an upper floor or in the attic rather than in the basement or lower level of a structure.

Ventilation ductwork also can be protected from flooding by locating it above the base flood level.

In addition to elevating large utilities, household appliances such as washing machines and dryers should be elevated above potential flood waters. (Illustration shows structure with 100 year flood level pointed out, and a concrete floodwall around the HVAC components below flood level. The HVAC components are also shown raised to the second floor or attic.)

Outdoor utilities such as heat pumps or air conditioners can be protected by placing them on an elevated platform above the base flood elevation (BFE). (Photo shows outdoor utilities raised above the base flood elevation.)

Unanchored heating oil or propane tanks can be easily moved by flood waters.  Losing these tanks results in major costs and inconvenience to their owners. If dislodged, these tanks also pose serious threats to public safety and to the environment.

An outside tank can be secured by running straps over it and attaching the straps to ground anchors. (Illustration shows propane tanks with tank anchors pointed out.)