Drinking water. In the walls, beneath the streets, around the world, it races through unseen pipes to fill tens of billions of glasses, cups, and bottles each day and to quench that most essential of human drives, thirst. For millions of years, intimate knowledge about the source of our water was among the most important bits of information our ancestors carried. Today that intimacy is lost. We turn on a tap and water flows as if by magic. We have come to accept the illusion as reality. Most of us have little awareness of the source of our drinking water. We assume it will be there. We assume it will be safe.
The road to disaster is paved with assumptions. The largest waterborne outbreak in U.S. history happened not centuries ago, but in 1993. Not only does waterborne disease still happen, but we don’t even know how often it occurs. Our system for detecting waterborne disease is so limited that drinking water is never even recognized as the cause in the vast majority of cases. Evidence suggests that drinking water may sicken millions of people every year in the United States.
For much of the developing world, waterborne disease is no secret. Like a tsunami in slow motion, unsafe drinking water is killing constantly; almost forty thousand people will die this week alone. Unlike a tsunami, it never stops.
In 1994 cholera swept through a crowded refugee camp in Goma, Zaire, and killed sixty thousand people in less than a month. It was the worst outbreak of waterborne disease in human history. The horror of Goma lies so far beyond the realm of experience for most of us that it takes on a sense of the remote and abstract. The gap between an epidemic in Goma and the sanitary comfort of the developed world seems vast, but for many reasons, this chasm may not be as immense as we imagine. Just a hundred years ago, waterborne typhoid fever was a leading cause of death in the United States. Less than fifty years before that, the major cities of Europe and North America were ravaged by waterborne cholera. The only thing that separates us from Goma is the systems we have developed to transport and treat our sewage and drinking water.
The operation of our water supplies is, to most of us, invisible. Invisibility encourages complacency. We have come to think of these systems as failsafe, but the technology we rely on for treating most of our drinking water is almost a century old and many of our water treatment plants have been in operation since the early twentieth century.
At least some of the water from these aging plants is, quite literally, treated sewage. Farm runoff, industrial waste, and sewage, both treated and untreated, routinely find their way to the intakes of our water treatment plants. Studies have shown that some of the pathogens (disease-causing microbes) from these sources can and do make their way into drinking water supplies, sometimes causing devastating outbreaks and frequently causing sporadic cases of disease. These diseases are not as deadly as cholera, but it is possible that this may not always hold true.
To understand where this story might lead, we must turn to its beginning. We must go back to a time when the difference between Goma and the developed world was far smaller, a time when we understood far less about health and disease and had no idea that a glass of water could kill.
In 1827, the industrial revolution was redefining the cities of the world. These population centers had grown over centuries from their agrarian roots into centers for commerce, education, religion, and government. Then, in a matter of decades, they had become the foundation of an uncharted industrial future, but remained propped on a rickety, haphazard infrastructure. Ill equipped to handle the influx of workers and the excreta of industry, these cities were straining at the seams. Filth and squalor grew in lockstep with urban populations. On the back of squalor rode epidemic diseases. When that happened the remarkably backward world of eighteenth century medicine would find itself scrambling to understand the causes of these diseases to identify the mechanisms for their control. At stake was nothing less than the viability of the industrial city.