I don't think I should be the one to say this because I drink next to no water ever (yay Milk & Soda) but Water is very good for your water's functionality and in particular your brain. In fact, if you get headaches frequently like myself, more water is calling because your brain needs water to work properly as it is made up of water primarily.
http://www.naturodoc.com/library/nutrition/water.htm
There is plenty of information on this subject, just use searching :-).
Slmclarengt