Without water, life would not exist on earth. Without drinking water, humans cannot survive. Without safe drinking water, people cannot remain disease-free. Harmful parasites, bacteria, and viruses all inhabit fresh water, and if we are to have safe drinking water, they must be killed or removed. The New Testament enjoins, “Drink no longer water, but use a little wine for thy stomach’s sake and thine often infirmities.” Today, we all assume that municipal water delivered into our homes is safe to drink. It was not always so.

Massachusetts established a state hygienic laboratory in 1886, and William T. Sedgwick, perhaps the first of America’s great sanitarians, was the state bacteriologist at that facility. Sedgwick identified the town’s contaminated drinking water as the cause of a typhoid fever outbreak in Lowell, Massachusetts, and this led to the construction in that community of the first North American municipal water filtration plant. Although chlorination of water, the technique most widely used today to render water free of disease- producing microorganisms, had been used for some time in Europe, it was not introduced into North American water supply systems until 1908 when it was first applied in Jersey City, New Jersey.3 Even today, although safe drinking water is widely available to them, many North Americans and Europeans buy bottled drinking water at prices exceeding what they pay for gasoline.

The recognition that specific microorganisms cause disease emerged in Europe with the dawning of the Renaissance, although smallpox and plague were already well known— even earlier in Asia—and were widely recognized as contagious by the general public, if not by physicians. Hieronymus Frascatorius of Verona is often cited as the first European to argue for the infectious nature of many diseases. His 1584 list of contagious ailments included “scabies, phthisis, itch, baldness, elephantiasis, and others of this sort.” In 1683, Antonj van Leeuwenhoek used one of his primitive, simple microscopes to examine the “scurf” of his teeth and, to his “great surprise perceived … many small Animals, which moved themselves very extravagantly.”