They tell us that to live sustainably we should do things like take shorter showers, make sure we don't leave the water running while we are brushing our teeth, and so on.
According to the Marketplace story "An oil refinery secures an essential material: water," "your shower uses about three gallons a minute. The vast BP oil refinery in south Los Angeles uses thousands of gallons a minute, 24 hours a day."
Maybe we should worry less about the length of our showers and more about building a society that is not so dependent on fossil fuels.
Shorter showers is easier though than transforming society. The easy things are a start, but doing the easy things is not an excuse to ignore the hard things.