Why Does Bottled Water Have an Expiration Date?

Q: Why does a bottle of water have a "best by" or “drink by” date on it when common sense dictates that water doesn’t go bad?

A: A 1987 NJ state law required all food products sold there to display an expiration date of two years or less from the date of manufacture. Separate labels for New Jersey seemed inefficient, so every bottle of water received a two-year expiration date, no matter where it was going. The lawwas amended a few years ago, but the expiration date has been an industry norm for so long that many producers have just kept it on there.