Does Bottled Water Ever Expire?

Bottled water is just about as simple a prep as can be had. Water is essential to life and hygiene, and most folks properly begin their journey to emergency preparedness with the first baby step of stashing an extra case of bottled water.

Over time, one case becomes two, then 24, then who knows how many, all the while that first lonely case sits dusty and smothered at the bottom of the stack. Preppers worry plenty about rotating perishable food but water gets nary a thought. Why should they? Water cannot expire like food does, right?

How long does bottled water last, anyway?

Water that is bottled and sealed commercially does not expire, even though it has an expiration or “best by” date. Bottled water though can, over time, begin to taste worse and worse as it leeches chemicals from its container. Additionally, algae and other unpalatable but otherwise harmless microbes can bloom in bottled water that has a broken seal and has been stored for a long time.

water bottles

If it does not go bad, why does it have an expiration date?!

Simple. Some states have mandated that all food and drink packaged and sold commercially has one. That’s it. New Jersey is one well known offender, standing strong against all common sense. They probably put peanut butter in the fridge, too.

At any rate, manufacturers making products on an enormous scale and servicing a regional or national market will invariably standardize their packaging when they can to save cost and streamline production logistics.

Ever notice that garishly huge tag hanging off all your new upholstery, furniture and other “home” goods? That is typically thanks to California’s Proposition 65 mandate. Thanks to them, most furniture makers will attach that tag to all their products just to ease distribution. That same intent applies to bottled water.

How Will I know it has Gone Bad?

You won’t, really. Like I said above, water that is sealed and factory bottled will last basically forever, but not without noticeable changes. A plastic or bad taste in a freshly opened bottle of water does not mean the water is not safe to drink, or otherwise unsafe aside from being unpalatable.

Conversely, fresh, crisp, clear, smooth tasting water taken from a mountain stream may be hideously contaminated and a death sentence. There are too many variables in the characteristics of possible contaminants to surmise all possibilities in this short article.

What is likely is that you’ll open a long-loitering bottle of water and try a sip to discover it tastes slightly burnt, plastic-y, or just off. Water is the universal solvent, and over time it will dissolve or weaken virtually everything. That taste, assuming the bottler did not just pour tap water into their tanks for bottling, is a result of chemicals leaching from the packaging into the water.

Now, before you flip your wig, know that these exact same chemicals are present in greater or lesser amounts in factory new bottles of water. If you trust the scientists, they assure us that those chemicals are in no way harmful in those amounts that are present.

What About Water that has been Opened or is not Sealed?

The script flips on water that is no longer sealed or was never sealed to begin with, especially if you drink from it and put it away. Any water that is not sealed may be contaminated by gribbles ranging from bacteria to algae.

The rule of thumb is you should seek to consume or dispense with “opened” water within two weeks or else you might court some microorganisms getting the party started in your water supply.

Bacteria needs no introduction and will multiply furiously in water if conditions are right. The wrong bacteria can make you grievously ill or even kill you, though the latter is rare. Good water filters as well as boiling or other sterilization methods will take care of bacteria easily.

Algae will likewise multiply, but most species are harmless. It will though create a nasty looking and occasionally foul smelling green goop on the walls of the vessel and often bobbing atop the water’s surface like a lily pad.

This is almost always enough to convince people to throw it out, but such water can be filtered for palatability. In a pinch, you can drink green algae right down with no ill-effects, and even get a little more protein in the bargain!

Large Container Shelf Life

If, like many preppers, you decide to store your own water in large containers, like 55 gallon water drums, you’ll have to be diligent if you don’t want to babysit them constantly.

Since you are likely filling these yourself prior to “capping” them, you will not have the benefit of multi-million dollar bottling machinery to make sure the water going into the bottle prior to sealing is completely free of biological contaminants.

This means you must be ferociously diligent about keeping the container as close to sterile as possible and the water going in must likewise be free of contaminants.

Regardless, chances are you’ll need to treat the water periodically during storage to keep it germ and algae free. Aside from that additional upkeep protocol, the containers themselves are no more dangerous than bottles for keeping water long term and will leech similar chemicals.

Bottom Line

Sealed, bottled water does not expire, though slow degradation of its container will affect its taste. The amount of chemicals leeched into bottled water by this process is not harmful in the amounts they will be present in.

Bottled water with seals cracked will eventually become contaminated and overtaken by bacteria and/or algae, necessitating purification.

A water source that has been directly drunk from will rapidly be contaminated by bacteria and/or algae: consider finishing the rest of it or treating it as soon as possible.

If your water is factory bottled and sealed you don’t need to worry about expiry dates on the package or on the bottles so long as you are not worried about a little off taste.

bottled water expiration Pinterest image

About Tom Marlowe

Tom Marlowe
Tom Marlowe practically grew up with a gun in his hand, and has held all kinds of jobs in the gun industry: range safety, sales, instruction and consulting, Tom has the experience to help civilian shooters figure out what will work best for them.

5 comments

  1. Avatar

    As far as barrels are concerned, exactly how is algae going to develop in a container that does not allow light to pass through it?

    Other sources say that if chlorinated drinking water is used to fill the barrel, the water will not develop bacteria levels. Are you sure about the need to re-treat the water periodically?

  2. Avatar

    Every single bottled water that I’ve had (and other liquids, like Gatoraide) seems to “collapse” over time. The bottles sort of “suck in”, and if I open them, the bottle springs back into shape, with the liquid level lower than when new.

    I don’t think water can “shrink”, so either there is a chemical reaction which results in a denser compound, or some of the water is “migrating” out through the bottle.

  3. Avatar

    Thanks for the article. . My main question is about BPA’s. Any thoughts on that?

  4. Avatar

    In my limited experience, material and storage conditions matter. I had my storage water in my garage in Phoenix, AZ at one time. The heat definitely made a difference. With polypropylene bottles (milk bottle type, but bought sealed from the store) after six months the water had a nasty aftertaste. After a year, it was all but undrinkable – the swallow I took burned my throat for the next few hours. Polyethylene clear bottles fared better, but still became nasty after a year, and had lost 30% or more of their original volume. I moved my water storage inside, and gave up using those polypropylene bottles as long term supplies.

  5. Avatar

    general advice has always been to change bottled water every 6 months, that’s about the time it takes for the plastic to start leeching into the water, bottled water should always be stored in a cool dry place out of direct sunlight.

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