http://news.sciencemag.org/sciencenow/2012/02/is-agriculture-sucking-fresh-wat.html
The average American uses enough water each year to fill an Olympic-
sized swimming pool, and global agriculture consumes a whopping 92% of
all fresh water used annually. Those are the conclusions of the most
comprehensive analysis to date of global water use, which also finds
that one-fifth of humankind’s water consumption flows across
international borders as “virtual water”—the water needed to produce a
commodity, such as meat or electronics, if the ultimate consumers were
to make it themselves rather than outsource its growth or
manufacture....