By Brian Cronin, Director of AquaMD

As is common this time of year, many parts of North America have experienced severe flooding as a result of the record rainfalls and spring thawing.

Many rivers, lakes and streams become swollen and flood hundreds of square miles in the central U.S. during this time. The resulting flood waters pose a health danger for anyone with a private well. The Environmental Protection Agency (EPA), Centers for Disease Control and Prevention (CDC) and the Health Department all strongly urge well owners within these flooded areas need to test their drinking water immediately.

People living in these flooded areas should take precautions to determine if their wells have been contaminated. Flooding will literally wash the land surface of many harmful contaminants, and will transport these pollutants across many miles. As the underground aquifers that feed all private wells are recharged by surface water, flooding poses a tremendous risk to ground water quality.

Chemical and Biological Contaminants

Besides the risk of chemical contamination, naturally occurring biological contaminants, such as bacteria, viruses and parasites, are transported by flood waters and can enter into private wells. Water-borne contaminants can enter private wells through loose-fitting well caps or by seeping down along a well’s shaft casing. The result is contaminated water that is unsafe for drinking, bathing, brushing teeth and preparing food. Shallow wells and wells found in low-lying areas are
especially susceptible to flood contamination.

AquaMD urges the owners of private wells to check their wells for signs of contamination and to test their water with a certified laboratory. If contamination is detected, the actual well water and home's plumbing system should be disinfected using treatment chemicals.

If well owners notice ANY change in their water quality--odor, color, sediment, taste, etc.--they must assume that their drinking water is contaminated and conduct a certified test immediately (however, please also be aware that many contaminants cannot be detected by human senses).

Wells That Don’t Appear Flooded are Also Vulnerable

Just because your own well has not experienced severe flooding, you should not assume your water is safe. Underground aquifers are often replenished by surface water run-off coming from many miles away. Even though your well may not have been flooded, other nearby wells that also tap into your aquifer may have been flooded. In the case of shallow wells, your water is vulnerable to contamination entering shallow aquifers through cracks and crevices, if the surrounding area becomes flooded.

Water and health all agree that if well contamination is even suspected, you should obtain water for drinking and cooking from a safe source, like an emergency community water supply or bottled water. Boiling water can provide protection against bacterial contamination, but may not protect against an assortment of chemicals, like Volatile Organic Compounds (VOCs), herbicides or pesticides.

To summarize, if your area has experienced severe flooding recently, you really should have your well water tested before resuming normal use. It's just good common sense.