where do most cities get their water supply
Drinking water supply and sanitation in the United States The centralized drinking water supply infrastructure in the United States consists of dams and reservoirs, well fields, pumping stations, aqueducts for the transport of large quantities of water over long distances, water treatment plants, reservoirs in the distribution system (including water towers), and 1.8 million miles of distribution lines.[5]:14 Depending on the location and quality of the water source, all or some of these elements may be present in a particular water supply system. In addition to this infrastructure for centralized network distribution, 14.5% of Americans rely on their own water sources, usually wells.[11][12]
Water distribution on Earth The planet's fresh water is also very unevenly distributed. Although in warm periods such as the Mesozoic and Paleogene when there were no glaciers anywhere on the planet all fresh water was found in rivers and streams, today most fresh water exists in the form of ice, snow, groundwater and soil moisture, with only 0.3% in liquid form on the surface. Of the liquid surface fresh water, 87% is contained in lakes, 11% in swamps, and only 2% in rivers. Small quantities of water also exist in the atmosphere and in living beings. Of these sources, only river water is generally valuable.