Why do bottled waters have expiration dates on them?

You'd figure that water would be the last drink to have an expiration date on it. After all, if earth's most natural drink could expire, we'd all be in trouble. But the bottled water industry has several reasons for putting expiration dates on its bottles.

First there is perception. Consumers intuitively associate a distant expiration date with freshness. Then there is container "break down." The deterioration of the bottle, especially a plastic bottle, gives water a bad taste. Lastly, the industry has legal regulations to comply with. In the US for example, at least one state--New Jersey--requires that bottled waters have expiration dates. Since it's cheaper for bottlers to put expiration dates on all their bottles than to make separate bottles for the states that require them, every bottle of water sold in the US has an expiration date.

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