Water Use - Trends In Water Use Since 1995

After continual increases in U.S. total water withdrawals since the USGS began reporting in 1950, water use peaked in 1980, declined through 1990, and has remained relatively stable since then. From 1995 to 2000 (the latest data available), a period that experienced a 7% increase in U.S. population, total off-stream water use increased only 2%. Water use for public supply increased by 8%, irrigation by 2%, and thermoelectric power use by 3%. (See Table 2.9, Figure 2.6, and Figure 2.7.)

Experts believed the general increase in water use from 1950 to 1980 and the decrease from 1980 to 2000 could be attributed to several factors, including:

• Expansion of irrigation systems and increases in energy development from 1950 to 1980.
• The development and increasing use of two irrigation methods—center-pivot irrigation systems and drip irrigation (the application of water directly to the roots of plants)—that are more efficient in delivering water to crops than the traditional sprayer arms that project the water into the air, where much is lost to wind and evaporation.
• Higher energy prices in the 1970s and a decrease in groundwater levels in some areas increased the cost of irrigation water.
• A downturn in the farm economy in the 1980s, which reduced demands for irrigation water.
• New industrial technologies requiring less water, improved efficiency, increased water recycling, higher energy prices, and changes in the law to reduce pollution.
• Active conservation programs and increased awareness by the general public of the need to conserve water.