How to Protect Against Flood Water

No matter where you live, you could at some point experience flooding. High water isn't just a hazard for people on the coast. Floods are one of the most common hazards in the United States, and changing weather patterns and an increasing number of hard surfaces like roads and sidewalks are putting more homeowners at risk for floods. Homeowner's insurance rarely covers flood losses, and federal disaster assistance is available only if the president formally declares a disaster. But even when disaster assistance is provided, it's usually a loan that has to be repaid with interest.

There are a number of steps that can be taken to protect a home from flooding. The Federal Emergency Management Agency (FEMA) suggests the following ways to provide flood protection.

Build With Flood-Resistant Materials
Building materials are considered flood-resistant if they can withstand direct contact with flood waters for at least 72 hours without being significantly damaged. Significant damage means any damage that requires more than low-cost, cosmetic repairs. Flood-resistant materials should be used for walls, floors and other parts of a home that are below the 100-year flood level. Commonly available flood-resistant materials include concrete, closed-cell and foam insulation, pressure-treated and marine-grade plywood, and ceramic tile. Keep in mind that all hardware used in these areas should be made of stainless or galvanized steel.

Add Waterproof Veneer to Exterior Walls
Even in areas where floodwaters are less than two feet deep, a home can be severely damaged if water reaches the interior. To protect a home from shallow flooding, add a waterproof veneer to the exterior walls. In addition, it's important to make changes to the interior walls as well. In areas below the flood level, replace bad insulation with washable closed-cell foam insulation. Any wood blocking added inside the wall cavity should be made of exterior-grade lumber.

Raise Electrical System Components
Electrical-system components such as service panels, meters, switches and outlets are easily damaged by floodwater. If they are inundated for even short periods, they will probably have to be replaced. Another serious problem is the potential for fires caused by short circuits. All components of the electrical system, including the wiring, should be raised at least a foot above the flood level.

Anchor and ELEVATE Fuel Tanks
Floodwaters can easily move unanchored fuel tanks, a situation that poses serious threats. An unanchored tank outside a home can be driven into the walls by flood waters or swept downstream where it can damage other property.

When floodwaters move an unanchored tank in a basement, the supply line can tear free and contaminate the basement with oil. One way to anchor a tank is to attach it to an elevated concrete slab heavy enough to resist the force of floodwaters. This can be done for all tanks, both inside and outside a home.

An outside tank can also be anchored by running straps over it and attaching them to ground anchors. The tank must be elevated higher than the base flood elevation to be in compliance with your local floodplain ordinance.

Raise or Flood-Proof HVAC Equipment
HVAC equipment, such as a furnace or a water heater, can be damaged extensively if floodwaters inundate it. To protect HVAC equipment in flood-prone homes, move it from the basement or lower level of the home to an upper level or even the attic. A less desirable method is to leave the equipment where it is and build a concrete or masonry block flood wall around it.

Install Sewer Back-Flow Valves
In some flood-prone areas, flooding can cause sewage from sanitary sewer lines to back up into homes through the drainpipes. These backups not only cause damage that's difficult to repair, but also create health hazards. A good way to protect a home from sewage backups is to install back-flow valves, which are designed to temporarily block drainpipes and prevent flow into the home.

Protect Wells from Contamination
Floodwaters often carry hazardous and toxic materials, including raw sewage, animal waste, oil, gasoline, solvents and chemicals. Floodwater that enters a well can contaminate the groundwater and make the well water unsafe to drink or use, and the effects may last long after the floodwaters have receded.

Taking steps to construct a well properly will help protect a well against contamination. For example, by extending the well casing at least two feet above the highest known flood elevation can prevent flood water access in most situations. Keep in mind that potential contaminants should be stored within 100 feet of the well.

Please contact the City if you have any questions regarding flood hazard information, flood insurance rating data, natural floodplain functions that should be protected or general floodplain requirements. Property protection assistance and/or property advice is available after a site visit. All elevation certificates on file with the City are available for review upon request. For further questions regarding flood damage and safety measures, please contact Director of Community Development, Mike Zeek, at or (314) 291-6550.

A shed in a flooded tree farm is photographed, with a cloudy sky in sunset reflected against the flood water