Waste, Work, and Worth
For most of human history, people could be divided into two classes: those who carried their daily water, and an elite who had someone else carry it for them. Water is quite heavy; approximately 8 pounds per gallon and moving it takes work. As a result, it is little surprise that people who have to carry water use only a few gallons a day for drinking, cooking, bathing, and cleaning. When water can be supplied without human work, the amount of water used each day increases dramatically. In Rome, at the time of the empire, water was delivered to neighborhood fountains, apartment buildings, and the residences of the wealthy, so affluent citizens used up to the luxurious volume of 150 gallons per day. The correlation between work and water exemplifies the classic parable of technological innovation, in which human labor is replaced by mechanical (or hydraulic) ingenuity and the amounts of work (or water) that can be delivered are dramatically increased.
…excerpt from “Waste, Work, and Worth,” in The Terrain of Water, Anu Mathur, Ed. (Forthcoming, 2013)