Our clean water infrastructure built a century ago is rusting and eroding apart, making the invasion of disease causing micro-organisms during floods even more likely.

excerpt from Before the Lights Go Out: Conquering the Energy Crisis Before It Conquers Us (John Wiley & Sons, 2012), by Maggie Koerth-Baker.

When you combine warm water and flash flooding, you get a risk of water-borne disease. That’s because many harmful microorganisms favor higher temperatures. If floods overwhelm water-treatment facilities, those organisms can find their way into the pipes, out of the tap, and into your glass. This isn’t something that happens only in underdeveloped countries or other places we can write off as “not like home.” The sanitation infrastructure of American metro areas is impressive, but it’s not infallible. Many parts of the Midwest have experienced increased precipitation from more numerous large storms. This isn’t only a Kansas problem. In 1993, Milwaukee, Wisconsin, suffered an outbreak of gastrointestinal disease caused by the bacteria Cryptosporidium. This bacteria doesn’t merely give you a tummy ache. Instead, it leads to a week or more of diarrhea, cramps, vomiting, and fever. Fifty-four people died. Just before the illness struck, the region had received its heaviest rainfall in fifty years.

Since 1993, researchers have found that heavy rainfalls are associated with higher levels of potentially dangerous bacteria. This has been measured in drinking water and in recreational waters. It’s also turned up in floodwater. In 2008, when major flooding inundated Iowa City and Cedar Rapids, Iowa, raw sewage came right out of the Cedar Rapids water-treatment plant and into the flood. Those contaminated waters sloshed into people’s houses, and when the water finally receded, it left behind buildings full of muck and mold. The people tasked with cleanup duties suffered from what they called “flood crud,” weeks of fatigue, cough, and other respiratory symptoms.