This is a really interesting article which was passed on to me from a participant at the Outlook Event in Washington. It is worth a read.

http://www.nytimes.com/2007/10/21/magazine/21water-t.html?_r=1&incamp=article_popular&oref=slogin&adxnnlx=1193412783-V5RHRZd5hDkLDap1s6qrLw&pagewanted=all