Cover Story
Flushing Out Disease
For a staple of life, water sure can cause a lot of trouble. Disease-bearing microbes, like the ones responsible for cholera and typhoid, happily hitchhike in the water from one city to another, infecting thousands of people along the way. A single cholera epidemic in London in 1848 claimed 14,600 lives.
These epidemics didn't become a matter of life and death in the United States until the mid-1800s, when cities proliferated, population density spiked, and more people were connected by waterways.
"Cholera is really a 19th-century disease," says David Rosner, a professor of history and public health at Columbia University. "Before that, epidemics were located in very specific places and tended not to travel very far."
As both population and industry grew, cities that had relied on nearby rivers found their water contaminated with the sewage and chemical waste of everything upstream. At around the same time, the first epidemiologists were rethinking how diseases like cholera spread and debunking assumptions that the plagues were airborne. In 1854, British physician John Snow famously traced an outbreak of cholera in London's Soho district to a single water pump, lending strong evidence to the notion that water was responsible for the spread of the deadly disease.
Before the practice of chlorinating water became common in the United States in the early 20th century, many cities combated the spread of waterborne diseases by bringing in water from more remote sources and separating their water supplies. New York City drew much of its water from the Croton River in modern-day Westchester County and later began tapping the Catskills with a lengthy series of aqueducts. Federal regulations slowly caught up with state efforts to mandate cleaner water, culminating in the Safe Drinking Water Act in 1974. Outside the United States, however, limited access to potable water remains a debilitating health hazard in many developing countries. –Chris Wilson
More on water conservation, including a video: www.usnews.com/water
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