Figuring out whether water expires is simple. It's a little more complicated to determine whether or not it's safe to drink.
Does Water Expire—And Just How Safe Is It to Drink Old Water?
Updated on May 13, 2025
Even if you love your reusable water bottles, you probably always have some bottled water on hand—maybe even stocked up in case of emergency (as you should). But have you ever wondered, Does water expire? Most of us think of it as a nonperishable food, but it turns out that bottled water won’t last forever.
So when was the last time you checked the expiration date on your bottled water? If it’s been a while, this article is for you. We dove into the research and regulations to find out if water ever goes bad and whether there’s a risk of drinking old water. Read on before you sip stale water.
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Does water expire?
It depends on the source. While you might find an expiration date on some bottles, the Food and Drug Administration (FDA) doesn’t mandate an expiration date on bottled water. You won’t find an FDA take on the current site, but in a 2002 issue of the agency’s Food Safety Magazine, it maintained that bottled water has an indefinite shelf life as long as it has been produced in accordance with quality standard regulations and stored in unopened, properly sealed containers.
On the other hand, the Federal Emergency Management Agency (FEMA) believes tap water lasts approximately six months if stored properly, as it doesn’t come from as highly regulated a place as bottled water.
Is it OK to drink expired water?
Nope, you’ll want to avoid sipping tap water that’s been stored for longer than six months. As for bottled water, the FDA may say it lasts indefinitely, but there are expiration dates on the bottles you buy. So does water expire or not?
Even though unopened bottled water is not at risk of microbial contamination when stored at room temperature, it is at risk of accumulating chemicals from the plastic that the water comes packaged in, usually polyethylene terephthalate (PET) for smaller bottles and high-density polyethylene (HDPE) for water cooler jugs.
In other words, it’s the bottle that goes bad, not the water.
A University of Heidelberg study confirmed that the longer water is stored in plastic bottles, the more it accumulates harmful chemicals. Later findings revealed that the concentration of these chemicals increased dramatically when the bottles were exposed to heat, including sunlight and hot cars or storage trunks. The chemicals identified in these studies, including antimony and bisphenol A (BPA), are linked to fertility issues, breast and prostate cancers, stomach ulcers and vomiting, among other health issues.
Additionally, the International Bottled Water Association highlights that plastic containers are slightly permeable, so if your bottled water is stored near household chemicals like paint thinners or household cleaners, the vapors from these chemicals may affect the taste and smell of the water. In rare cases, when water is exposed to extended periods of direct sunlight or heat, it can also grow mold or algae.
Ultimately, if your bottled water has been stored in a cool, dry place out of direct sunlight and away from solvents or chemicals—no matter for how long—it should be fine to drink.
How long does it take for water to expire?
Though it’s a bit arbitrary, many bottled water companies print a standard two-year expiration date. There’s no precise way to predict exactly when the water in the bottle is no longer good to drink, but the longer the water has been in the bottle, the more likely it was exposed to heat or has accumulated harmful chemicals.
Though the FDA doesn’t mandate printing expiration dates for bottled water, many companies still include best-by dates as a precautionary measure. While the water may be safe to drink, it’s always good to be cautious and store bottled water properly to keep its quality intact.
Can you get sick from drinking old water?
While technically, yes, you can get sick from contaminated or exposed bottled water, it’s pretty rare. As a general rule, as long as you drink it reasonably soon after you buy it, don’t expose it to long-term intense heat or keep it too close to any household chemicals, and refrigerate it once it’s open, your bottled water should be perfectly safe.
FAQs
How can you tell if bottled water has gone bad?
Look for a strange smell, odd taste, cloudiness, mold or bloating of the bottle. As a study published in Food and Chemical Toxicology points out, discoloration is another sign you shouldn’t drink a bottle of water.
Can you boil expired bottled water to make it safe?
No, boiling kills germs, but it won’t get rid of the chemicals from degraded plastic. If your bottled water has gone long past its expiration date, you’re better off throwing it away.
What’s the best way to store emergency bottled water?
According to the International Bottled Water Association, you should keep commercially bottled water at room temperature or cooler, out of direct sunlight, away from chemicals and in a cool, dark place.
If you are storing tap water, the U.S. Department of Homeland Security recommends thoroughly cleaning your bottles with dishwashing soap and water, then filling them with regular tap water. If you are using water from a well or an untreated source, add two drops of unscented liquid household chlorine bleach to each gallon of water. Seal tightly with the original cap, write the date and store in a cool, dark place away from sunlight or chemicals. Rotate the stock every six months.
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Sources:
- FDA: “Bottled Water Everywhere: Keeping It Safe”
- Food Safety Magazine: “Bottled Water Regulation and the FDA”
- International Bottled Water Association: “Bottled Water Storage”
- Federal Emergency Management Agency: “Food and Water”
- CBC News: “Plastic bottles leach chemicals into water: study”
- Acta Biomedica: “The effect of temperature and storage time on the migration of antimony from polyethylene terephthalate (PET) into commercial bottled water in Kuwait”
- Environmental Pollution: “Effects of storage temperature and duration on release of antimony and bisphenol A from polyethylene terephthalate drinking water bottles of China”
- Science of the Total Environment: “An evaluation of the migration of antimony from polyethylene terephthalate (PET) plastic used for bottled drinking water”
- Food and Chemical Toxicology: “Deterioration of the quality of packaged potable water (bottled water) exposed to sunlight for a prolonged period: An implication for public health”
- Ready.gov: “Water”
