While the different computer models of global warming don’t agree on everything, they do agree that warmer temperatures will lead to increased rainfall. This increase in rainfall will in turn lead to more disease-carrying agents in our drinking water.
Heavy rainfalls often trigger sewage overflows that contaminate drinking water. Consequences will be most severe in the nearly 1,000 U.S. cities (including New York, Washington DC, and Milwaukee, and Philadelphia) that have sewer systems which use the same pipes for storm water and sewage. When the pipes cannot handle heavy rain, raw sewage spills into drinking water supplies.
In 1993, for example, heavy rains in Milwaukee led to a sewage release that exposed 400,000 people to cryptosporidium, a parasite transmitted in fecal matter. The protozoan parasite killed 54 people.
Paul Epstein of Harvard University explains in the Washington Post: “Raw sewage got sucked back into the clean water supplies. Cryptosporidium is a parasite that chlorine doesn’t kill, so it escaped water treatment.”
When officials must choose between urban flooding and water contamination, they will inevitably choose water contamination to minimize damages. You must take steps to make sure that your water is clean, especially if you live in an older city with a combined sewer system. Filtering your water with a home water purifier is the best way to ensure that you’re drinking clean water.