In the United States, we tend to take our clean drinking water for granted. Even though there are periodic concerns which bubble up about pharmaceuticals or other chemicals in our water supply, we typically believe--with good reason--that we have little to fear when it comes to contamination from microbes. Our drinking water, while far from perfect, is heads and shoulders above what it once was--something many of us forget or have never realized. There have been notable breakdowns, such as the 1993 outbreak of Cryptosporidium in Milwaukee that sickened over 400,000 individuals, but these days…