Tap water is a revolutionary invention, involving both the coordinated distribution of clean water and the treatment of wastewater.  The ability of most US city dwellers to have a reliable source of clean, safe tap water always at hand has been with us for only about the past two centuries.

The need for a water system first arose when humans invented agriculture, and early water systems were designed primarily to help crops grow.  Irrigation systems create conditions that can give rise to significant levels of contamination in water.  Runoff from irrigated fields, standing water in canals or trenches dug for agriculture or pent up behind dams, cisterns to store water – all of these can be both reservoirs for toxins and breeding grounds for microorganisms that cause disease, or insects that spread disease.  Agricultural civilizations stay put, rather than migrating to sources of cleaner or more abundant water. Even as the civilizing effects of agriculture allowed an increase in the size of the human population, it often resulted in a decrease in life expectancy – typically through high rates of infant mortality from exposure to contaminated water drawn directly from nearby lakes, rivers, streams, or wells.

How did earlier civilizations respond to the problem of contaminated water?  Some ancient civilizations, such as Rome, became adept at engineering ways to bring fresh water from mountain streams to public fountains.  Almost all civilizations used fermented fruit or grain to make wine or beer, which were in effect ways to sanitize water – the alcohol produced during fermentation would kill not only the yeast doing the fermenting, but other microorganisms as well.  Drinking beer or watered wine were popular ways to avoid water-caused illness.  Other civilizations relied on boiled water in beverages such as tea or coffee as ways to prevent such illnesses.

Unfortunately, as the populations in cities increased into the 17^th, 18^th, and 19^th centuries, the ability of cities to provide clean, safe water decreased – so much waste from both human bodies and manufacturing plants was dumped into nearby bodies of water that the quality of water available declined rapidly.  The invention of the flush toilet made the problem worse, as more human excrement found its way directly into rivers. 

England led the way in the development of sanitary sewer systems that soon became models throughout the West.  These systems assured that wastewater carried human and animal excrement and industrial pollution far downstream of cities’ water supplies. A famous example in the United States is the engineering of the Chicago river to flow backwards – rather than flowing naturally into Lake Michigan, which supplies drinking water for the city of Chicago, it was made to flow backwards into the Illinois and Mississippi Rivers, taking waste away from the city.  At the same time, methods such as sand filtration, and eventually chlorination, became common ways to pre-treat water before distributing it to homes.  Deaths from water-borne diseases dropped precipitously in the US.  Sadly these illnesses are still the number one cause of death in developing countries worldwide according to the World Health Organization.

An important point about the so-called “Sanitary Revolution” is that these had to be group efforts, involving either a governmental mandate or the formation of a private company to manage the systems.  A famous incident in London in the mid-19^th century, the “Great Stink” in which the Thames River was so overloaded with pollution that it created an intolerable stench, motivated Parliament to pass legislation that created London’s system of sanitary sewers.  These efforts were the forerunners of today’s municipal water systems, which began to spread in the US in the first decades of the 20^th century.  In 1850 the US had just over 80 public water supply systems; by the beginning of the 20^th century there were over 3000.

For further reading on the history of water systems in the US and worldwide:

• Privatization of Water Services in the United States: An Assessment of Issues and Experience — Chapter: 2. History of U.S. Water and Wastewater Systems.  National Academies Press, 2002. https://www.nap.edu/read/10135/chapter/4#36
• Doyle, Martin. The Source:  How Rivers Made America and America Remade Its Rivers. W. W. Norton, 2018.
• Solomon, Steven. Water:  The Epic Struggle For Wealth, Power, and Civilization. Harper Collins, 2010.