PET bottle water

Every year, millions of people buy bottled water for its convenience and portability. For people who have bottles of water sitting unused in their car or pantry, however, knowing whether the water is still usable can be a challenge.

Health Risks of Old Water

Old water is more likely to become contaminated with bacteria . Studies have also shown that some plastic water bottles will leach plastic chemicals into the water if placed into storage for too long. These chemicals have been shown to cause cancer in some laboratory animals.

How Soon Does Water Go Bad?

Most commercial bottled water is marked with a shelf life of two years. As long as each individual bottle remains sealed, it should be drinkable. Opened bottles of water should not be consumed if stored for over a week.

How to Determine if the Water is Too Old

Each container of commercially bottled water should have an expiration date stamped on it. For single-serving bottles of water, look near the cap on top of the bottle. For cases or pallets of water, look underneath at the cardboard packaging.


Bottled water is generally packaged in containers made out of the plastics PET (polyethylene terephthalate) and HDPE (high-density polyethylene). These plastics are somewhat porous, and water stored in these bottles will begin to take on the smell taste of its surroundings. If you've stored the water in your basement or garage for some time, the water may be unpleasant to drink.

Suggestions for Non-Drinkable Water

Even if the water is unsafe for human consumption or has picked up an odd smell or taste in storage, you don't need to throw it out. You can use the water on your plants, for example, or stash a few bottles in your car to use in your radiator in case of emergency.