H2O

A pound of grain uses less than 1% of the water used to produce a pound of meat. US agriculture uses 87% of the water used in the US. It takes 10,000 Kg of water to produce 1 Kg of beef while soy only uses 900 Kg and potatoes 500 Kg.

Source: US Could Feed 80 Million With Grain Livestock Eat, Cornell University Science News, August 1997