If you've flown anywhere in the last several years, you know you can't bring water through security. You need to purchase bottles of water once you have cleared security. If you need more than one bottle for a long trip, they get cumbersome to carry. Not to mention heavy.
Think about using the collapsible bottles that are basically flat when empty. Fill them up just before you board and you won't have to drag around heavy bottles.
After they are empty, store them in your carry on and reuse them next time.