Question:
Had some gallons of commercially bottled spring water that my wife insisted I buy after September 11. My daughter told her that if she insisted on buying bottled water to drink daily, then buy the gallons and refill the small ones. So I dragged out the gallons. I noticed that they had all passed the expiration date. How the hell does water go bad?

Answer: Soda companies began printing a "for best taste, drink by" date on their bottles a few years ago. I see a bottle I bought this week shows a date in early October. I have opened a bottle that was stored more than 3 years (back of cupboard) and was as fizzy and tasty as any more recent vintage. In this case, I believe the dates are more aimed at keeping inventory churning.

There's no particular reason that water would "go bad" upon storage. The bottled water industry is highly regulated,

http://www.bottledwater.org/public/BWFactsRegHome.htm

As for 'plastic chemicals leaching into the water,' then what of box wine, peanut butter, jam, soy sauce, oil, and thousands of other food products designed for long, unfrigerated shelf life?