Will we run out of water before fuel?

If I remember correctly, the magazine Nutrition Action (uses reliable peer-reviewed studies for information) confirmed that you need 8-12 cups of water/day - and that requirement can be mostly fulfilled via eating normal food. Drinking 12 cups of water each day in addition to consuming regular amounts of food is overzealous at best and dangerous at worst, assuming you aren't an athlete.

Now for the anecdote: I tried drinking 8 glasses of water per day for a week once, and I felt like total crap. 2/day and some juice, everything else comes from food and I'm 100% healthy.