The development of a system of indoor plumbing was typical of the technological breakthroughs that simplified everyday life in the late nineteenth century. In the 1860s only about 5 percent of American houses had running water. Most Americans used chamber pots or outhouses that emptied into slimy, smelly cesspools. Two decades later, indoor plumbing standards had been established in most major U.S. cities, and wealthier urban Americans used flush toilets connected to municipal sewer systems.

The driving force for change came from outbreaks of cholera, typhoid, and yellow fever, diseases spread by polluted water, that periodically terrorized American cities. Building upon the discovery of germs by Louis Pasteur and Robert Koch, sanitary reformers established stringent metropolitan health laws, created state boards of health, and mandated the licensing of plumbers and the inspection of their work. By the turn of the century, George E. Waring, Jr., a prominent sanitary engineer, could confidently declare that "Plumbing, as we know it, is essentially and almost exclusively an American Institution."

The decision to adopt a water-based system for the removal of human wastes depended on a series of inventions. First, municipal water systems had to be built with reservoirs, pumps, and water towers to provide water to the pipes that supplied buildings. A sewage system of interconnected pipes was also necessary to remove and process wastes. Machines to manufacture lead, cast-iron, and glazed stoneware pipes had to be created, as did a uniform system of pipe threads and melted lead joints to create a reliable standardized system for connecting them. Finally, a porcelain toilet with a built-in gas trap was needed because the bacteria in feces produce methane or sewer gas. (A trap is a U-shaped joint that uses the water at the low part of the U to prevent gas from seeping back into the bathroom. The gas is then vented through a pipe in the roof.)

Despite its usefulness, the new technology was adopted only slowly by Americans. In 1890 only 24 percent of American dwellings had running water. As late as 1897, over 90 percent of the families in tenements had no baths and had to wash in hallway sinks or courtyard hydrants. By 1920, 80 percent of American houses, particularly those in rural areas, still lacked indoor flush toilets. The reason was simple: indoor plumbing was expensive and depended on the availability of water and sewer systems. Adding indoor plumbing increased the price of a new house by 20 percent.

Advertisers did their best to increase demand. They skillfully used the findings of science to advocate new standards of cleanliness or "hygiene," as it was called, which they associated with upper-class principles of respectability and decorum. Bathing and washing one's hands were touted as symbols of upper-class refinement.

Indoor plumbing not only reinforced higher standards for personal hygiene; it also enmeshed the homeowner in a web of local and state regulations. As sewage and water systems expanded to cover larger constituencies, political control moved from local to state and sometimes national arenas. Once largely independent, the homeowner now had to deal with water and power companies that often functioned regionally.

The adoption of strict sanitation systems and the use of indoor plumbing did achieve their intended result: they dramatically reduced the spread of disease. But the advances had unintended consequences. Indoor plumbing encouraged the phenomenal waste of water. A single faulty toilet could easily leak a hundred gallons of water a day. Not until the 1990s with the development of new low-water-usage toilets, which could save between 18,000 and 26,400 gallons of water a year, would new standards be established to reduce the use of water, an increasingly precious natural resource.