That is n early 10 percent less than the total used in 1980, even though the population has grown. Economic downturn, water-saving technologies, higher water prices, and conservation efforts have stemmed water demand. Still, Americans remain among the world's biggest water users. The U. S. uses more water to produce electricity than for any other purpose. Electricity heats and cools buildings, drives trains, melts metals.
Water helps generate power through two different processes, thermoelectric and hydroelectric.
Thermoelectric plants, which convert water into steam by heating it with fossil or nuclear fuels, provide nearly 90 percent of U. S. electric power. Water from dammed reservoirs provides the gravity-driven force that turns turbines to energize dynamos. To produce one gallon of milk, a dairy cow must drink four gallons of water. It takes eight gallons of water to grow a tomato. Practiced extensively in the West, irrigation brings cotton to Arizona, potatoes to Idaho, tomatoes to California.