"Gallons of freshwater consumed in the production of a gallon of milk and beer, respectively: 1,000, 300."
- Harper's Index
This is worth remembering in Southwest Colorado, where water is relatively scarce.
Of course, the best thing you can drink for the environment is municipal tap water. Corporations have done a great job of convincing us that tap water is somehow tainted. It's fine. Especially in Durango, where it comes from the Weminuche Wilderness.
But you can't drink only water, and craft beer is a heck of an alternative.