On hot summer days, here in New York City, you will often see, at a stoplight in one of the neighborhoods where the traffic gets thick and slow, or in one of the places where the hapless pods of tourists find themselves most exposed to the sun’s pitiless rays, a young man or woman equipped with a blue Igloo ice chest and a lot of lungpower, pulsing out the standard cry of “Icecoldwateronedollar!”

These water-sellers are regarded by many—the rich, the comfortable, the provident and hydrated—as little more than public nuisances. And yet theirs is an ancient and honorable profession. Here in America, we are fortunate to have built the majority of our infrastructure after the development of indoor plumbing. That meant that, since the early nineteenth century, for us water was centrally distributed; something that flowed to each individual building, cheap, plentiful and, for the most part, reasonably clean.