Not a drop to drink

800 gallons of water to make one hamburger

If there are 650 gallons of water in a pound of cheddar cheese, is it futile to make small gestures like turning off the water when you brush your teeth in the name of saving it?

It helps with water bills, so it makes sense in that way. And it may make sense with local water resources, which may be constrained, just within a small town, or even a community.

At the global scale, no, it doesn't make much difference. Most of the water that each one of us uses comes from the water used to irrigate the crops that we consume. That's principally food, but not only. Cotton for our clothing is a major user of water around the world.

We don't really know as we pick up the food from the store whether our purchases are responsible for making some local crisis elsewhere worse, but it is often the case. Many countries are facing serious water shortages; often their rivers are running dry, or their water tables falling very fast, and in many cases much of that water is being exported by those countries in the form of goods. Yet, when we pay market price for those goods, that price doesn't usually include any estimate of the cost to the water resources. We still think of water as an unlimited resource rather like the air we breathe.
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Is the American lifestyle more consumptive of water than other counties, as it is of energy resources, like oil and natural gas? And do you think the U.S. might end up importing water going to war from with Canada in the future?

It's an issue that keeps coming up. Canada has a great deal of water, particularly in the West, and America has quite a lot of demand for water, particularly in the West. So, you can imagine circumstances under which the U.S. would like to get its hands on Canadian water. Canadians are adamantly opposed to this, and I think that you'd have a great deal of difficulty getting any water out of them. They are prepared to use their rivers to generate hydroelectricity to sell electricity to the U.S., but they're not prepared to sell their water.

Domestically, American users are among the highest water users in the world, but you [Americans] stabilized your water consumption in recent years, principally by having more efficient toilets that use much less water in the flush. Canadians have not changed their toilets in the same way. They are probably now the No. 1 domestic users of water in individual homes. But neither the U.S. nor Canada reaches anything like the per capita water consumption of Uzbekistan and Turkmenistan.