Have you ever seen an expiration date on your bottled water and wondered what’s possibly going to happen between November and December 2019 that will cause your water to spoil? The answer is: not much, but play it safe anyway.
For bottling companies, it began as matter of ease. When a 1987 New Jersey law required that bottled water not be sold more than two years after the bottling date, bottled water manufacturers simply printed the expiration date on all of their water instead of trying to determine what batches would end up in the Garden State.
In 2004, New Jersey dropped the expiration date requirement for bottled water—bottled water has an “indefinite shelf life,” the amended law says. While manufactures are still required to responsibly bottle the water and abide by the FDA’s good manufacturing rules, they’re now only expected to print the date of the bottling on their products.
New Jersey legislators leave it to bottling companies if they want to determine and print their own expiration date.
Manufacturers use the same machines to bottle water and soda.
And soda, unlike water, does have an expiration date. In order to streamline the operation, manufacturers simply print an expiration date on all bottled beverages.
So, even though bottled water doesn’t require the expiration date, it gets stamped on just like the rest.
There is still good reason not to drink really old bottled water.
The first issue is taste. Plastics are slightly porous, and over a long period of time, they can absorb the smells from around them. That means that your pristine spring water can take on a funky taste over time.
The second reason is more worrisome. Though the FDA hasn’t found specific dangers to drinking old bottled water, experts still worry about chemicals leaching from plastics.
George Bittner, a professor of biology at the University of Texas-Austin, has studied how plastic containers contaminate beverages. He told NPR that when plastics come into contact with high temperatures from sunlight or dishwashers, “you greatly increase the probability that you’re going to get chemicals [that mimic human hormones] released.”
Studies have also shown that leached chemicals increase over time in bottled water.
A study from the University of Heidelberg found that the concentration of various chemicals in water increased the longer it sat in a bottle. The study only tested the water after six months, but in that time frame, the levels of a chemical called antimony had doubled.
William Shotyk, the study’s lead researcher, told CBC News, “Antimony is similar chemically to lead. It is also a potentially toxic trace element.”
To be clear, the levels of antimony that Shotyk found were still well under the allowable limit. The more concerning part of the story, though, is that the levels could continue to rise as water sits on a shelf. So even though the expiration date may have been mandated by a now-defunct law, there may still be good reason to avoid ancient water bottles.