You'll get conflicting ideas on what people count "as water".
Anything wet hydrates you. Water is your best choice, followed by water as you're having it, then possibly plain tea, and then you're starting to get into the debate over diet sodas. But even regular sodas, coffees, and double choc whip half caf super mega frappucino grandes are still "wet" and still hydrate the body.
Try to limit anything other than water and choose water (even with Crystal Light) first, but yes, anything wet "is water".