Not serving people a glass of water is exactly the kind of distraction which prevents people from thinking rationally about what water is used for. It helps about the same as doing a rain dance with the bonus of making people irate about any other possible water usage they hear about before they've even had a chance to look at the full picture.

Remove all water usage by individuals and DCs and you've barely made a dent in water usage, so why is the solution supposed to be a compromise somewhere between the two?