A regular supply of water is one of the most basic necessities of human life. In fact, ancient societies and cultures developed on the banks of rivers because they sustained life. In the modern world this need is stronger than ever because water is now used for much more than simply drinking, cooking and washing. The supply of water has not kept up with its demand, simply because water bodies have stayed the same, while cities and civilizations have vastly expanded! In such a situation, it is wiser to pull water from other, faraway sources rather than depend upon the local ones. Philadelphia was the first American city to do so in the 19th century and its residents were rewarded with good health, industrial prosperity and Europe’s admiration for its technology. The water system developed by the Philadelphia engineers is used as the basis of most water systems today.
Water supply systems differ from region to region, depending upon the terrain and the reservoirs from which water is drawn. In New York, for instance, 95% of the movement of water is done using gravity and only 5% requires pumping through pipes. On the other hand, carrying water to a town atop a hill will require an entirely different system. Of crucial importance is the resource from which the water is drawn. Water may be drawn from surface water sources, ground water sources or sometimes by desalinating seawater. It is easy to imagine the inconvenience of not having a regular supply of water. But having to supply your own water can also be the cause of dangerous illnesses, because water drawn directly from rivers and lakes may contain contaminants and pollutants that are missing from a clean and treated supply of water.