I have a unique observation about water and teenagers.
I have 2 teenagers at home and a third child who desperately wants to be one; I cannot recently remember ever seeing one drink water from the tap. They consider it "bad or un-cool" and will go for juice, soda pop, milk or ice tea in the fridge.
The really odd thing is that if there is bottled water in the fridge (or even stored in the garage) they will drink that and are happy. They must figure that since you buy it and that it is in a bottle, it must be "good".
So I tend to buy bottled water (in large amounts, on sale) and have it available just to keep my kids from loading up on sugar that they do not need.
We do recycle all the plastic bottles, but I am constantly remind my kids to pick up the empties and put them in the bin!
Mike