Why is there an expiration date on my bottled water, and how long can I keep a bottle?

The expiration date may be there because, in some cases, the state requires every edible product to have one. Many water bottlers indicate a 2-year shelf life for their product. However, as long as properly bottled water is not open, it should be safe to drink, though the taste may deteriorate with the passage of time. (Bottled water contains no nutrients, so the pathogens that cause food-borne illness cannot grow in it.)
 
Once the bottle has been opened, refrigerate it, and keep the water no more than 2 weeks.
 
Source(s):
EHSO Environment, Health and Safety Online - “Drinking Water Information: Bottled Water or Tap Water?”