Chug this!
I’m about to jump all over this bandwagon. If for no other reason than it saves me the daily irksomeness of GTB leaving half drunk bottles of water all over the house and in my car, not to mention the rage-inducing annoyance at the half-empty (or half-full?) bottles he puts back in the refrigerator.
If asked though, I’m going to claim it’s because I’m so eco-conscious. And frugal.