This MayoClinic.com article says even mild dehydration — as little as a 1 percent to 2 percent loss of your body weight — can sap your energy and make you tired.
Lifehacker link to a wikiHow article on how to drink more water everyday. Not sure of the peer review process for wikiHow articles - this one says, "In some places, such as Philadelphia, the tap water actually contains the same electrolytes that are in Gatorade."
hmmmm..I don't know what electrolytes are, but it sounds like a good deal for people who live in Philadelphia.
In any case I'm a firm believer in the health benefits of water, and like to try and drink as much of it as I can.
