Science, Tech, Math › Science Does Bottled Water Go Bad? Share Flipboard Email Print Bottled water may carry an expiration date, but under typical storage conditions it does not go bad. baona/iStock Science Chemistry Chemistry In Everyday Life Basics Chemical Laws Molecules Periodic Table Projects & Experiments Scientific Method Biochemistry Physical Chemistry Medical Chemistry Famous Chemists Activities for Kids Abbreviations & Acronyms Biology Physics Geology Astronomy Weather & Climate By Anne Marie Helmenstine, Ph.D. Chemistry Expert Ph.D., Biomedical Sciences, University of Tennessee at Knoxville B.A., Physics and Mathematics, Hastings College Dr. Helmenstine holds a Ph.D. in biomedical sciences and is a science writer, educator, and consultant. She has taught science courses at the high school, college, and graduate levels. our editorial process Facebook Facebook Twitter Twitter Anne Marie Helmenstine, Ph.D. Updated January 22, 2019 Most bottled water has an expiration date stamped on the bottle, but does the bottled water actually go bad? If so, how long is bottled water good? The answer to this common question is fairly simple. Expiration Dates Come From a State Law Although bottled water has an expiration date, it doesn't actually go bad. Why is there an expiration date on a product that doesn't go bad? This is because the state of New Jersey requires all food and beverages, including water, to carry an expiration date on its packaging. It doesn't matter if you don't live in New Jersey...your water may carry an expiration date anyway to make it easier to standardize packaging. Some bottled water only carries its bottling date or a "best by" date. These dates are helpful because the flavor of the water will change over time as it absorbs chemicals from its packaging. The flavor will not necessarily be bad, but it may be noticeable. Any Leaching From Plastic Is Unrelated to Time Leaching of chemicals from packaging is a health concern, but as far as toxic chemicals go, you can get exposure to most of those chemicals from freshly bottled water as well as bottled water that has been on the shelf a while. A plastic taste is not necessarily an indicator that the water is bad; conversely, the absence of an unpleasant flavor does not mean the water is free from contaminants. Keep Bottled Water Sealed While algae and bacteria will not grow in sealed bottled water, the situation changes once the seal has been broken. You should consume or discard water within two weeks after opening it.