Exporting Water

Estimates of water use in the United States indicate 566 billion cubic meters per year (410 billion gallons per day) were withdrawn in 2005 (The latest USGS report - - Estimated Use of Water in the United States in 2005).  The breakdown by user segment in billion gallons per day:

• 349 billion gallons per day freshwater withdrawals
• 79.5 billion gallons per day fresh groundwater withdrawals
• 270 billion gallons per day fresh surface-water withdrawals
• 201 billion gallons per day thermoelectric-power generation withdrawals
• 128 billion gallons per day irrigation withdrawals
• 44.2 billion gallons per day public supply withdrawals
• 18.2 billion gallons per day of industrial self-supplied withdrawals
• 4.02 billion gallons per day of mining related withdrawals
• 2.14 billion gallons per day of livestock withdrawals
• 8.78 billion gallons per day of aquaculture withdrawals

The idea of a water export (or import) comes from exported food and products - - the United States exports water to other countries mainly via meats and cereals (your basic hamburger required 150 gallons of water to make it out the drive-thru at McDonald's).  Estimates of the U.S. virtual water exports are approximately 80,000 million cubic meters per year (See June 2012 issue of Scientific American, Water In, Water Out - - graphics are from the article).

Exports are roughly 14% of total annual U.S. water withdrawals.  Most of our virtual exported water comes from irrigation (176.8 billion cubic meters per year) and livestock (2.95 billion cubic meters per year).  Total U.S. water exports are 45% of the irrigation and livestock totals.

By comparison, the U.S. imports about 136.75 billion gallons of oil per year - - for every gallon of virtual water the U.S. exports, we import almost two gallons of oil.