Bottled Water Expiration Date
We've all been guilty of it—left a water bottle in the car, in a gym bag, or on a desk for goodness knows how long. Perhaps today you found one, had a few sips, then hesitated and thought, 'Wait… is this still okay to drink?'
It's a simple question, one that surprisingly finds relevance. Bottled water is said to last indefinitely. It's water, for crying out loud.
But then you see that "best before" date marked around the lid and start questioning everything. Can water ever expire? Or is the bottle guilty instead?
Whether you’re storing bottled water for emergencies, reusing an old bottle, or just forgot one under the seat of your car, it’s worth knowing what really happens to water over time.
In this article, we’ll break down what those expiration dates mean, what changes inside the bottle (especially if it’s been sitting in the heat), and whether drinking that old water could actually be bad for your health.
No panic, no fluff. Just facts and an explanation that makes sense.
Does Bottled Water Expire?
Okay, let's get one thing straight first: water itself never goes bad. It won't spoil or rot like food. But water in a bottle? That's another story.
When you see an expiration date printed on your plastic water bottle, it's not because the drinking water somehow goes bad after that date.
The FDA does not require bottled water to have an expiration date, but most manufacturers still include one, typically two years ahead. Why? Because of the bottle, and not the water inside.
Most commercially sold bottled water is stored in polyethylene terephthalate plastic. That plastic is somewhat permeable, so over the period of time it's stored, tiny particles of air and even carbon dioxide will move in.
That can spoil the taste, resulting in an odd or even stale flavor, especially if it's not stored in an ideal environment.
Temperature is involved, too. If your water bottle is left in a warm car or in the sun, it will accelerate chemical leaching, allowing tiny amounts of plastic chemicals to leach into your pristine water.
It's more of a problem over months or years, not days, but something to consider nevertheless.
Where bottled water is stored matters; a cooler location, such as a pantry or cupboard, is ideal. A dark space away from direct sunlight and heat? Better still. Putting water on your nightstand, in your vehicle, or outdoors in the sun for weeks on end? Not so good.
Bottom line: Bottled water never "expires" in the traditional sense, but the container can affect its safety, taste, and overall quality.
If the bottle is twisted, smells funny, or is past its expiration date and has not been stored well, it might be best to go pick up a fresh glass instead.
What Happens to Water Over Time?
If you would like to understand what happens when you consume stale water from a bottle, the reason is not so much to do with the water itself, but more to do with the bottle in which it has been stored.
Let’s start with this: water doesn’t spoil. But when it’s been left sitting in plastic bottles, especially in a hot car or next to a window, things start to change.
That plastic can begin to break down, and small amounts of chemicals like BPA or antimony can leach into the water. These aren’t great for your health, especially if you’re drinking them regularly.
You will also find that standing water left out for some time tastes unusual. That is not your imagination.
Chlorine (which is usually added to tap water or even some bottled water) will evaporate over time, which alters the flavor of the water.
Oxygen also seeps into it and distorts the flavor. This is why day-old water that has just been left standing in a glass or refillable container will have a slightly flat or "off" taste.
And now, after the seal is broken, that's when bacteria and even mold are able to enter, particularly if you've had a sip and simply left it sitting around.
Consider dirty hands, backwash, or just plain old air introducing microbes.
Warm temperatures only hasten the process. So, yes, public health issues can happen when you're routinely drinking off spoiled or stale water from open containers.
The longer water sits, especially in the wrong conditions, the more likely it is to have an off taste, possible chemicals, or even bacteria growing.
That doesn’t mean you’ll automatically get sick from one sip, but over time, it’s not worth the risk.
To ensure your drinking water is safe, always inspect the container. Is it warped? Cloudy? Odoriferous? If unsure, pour it out. It's better to have fresh water again than risk it with your gut.
Health Risks of Drinking Old Bottled Water
So, what if you consume old water from a bottle? The short response is: maybe nothing, or perhaps something that'll have you wishing for later.
Let's dissect it. If the bottle is sealed and properly stored (consider a cool location, out of direct sunlight), there's probably still safe drinking water inside, even if it's beyond the printed expiration date.
However, after the seal is broken, or if the bottle was left in a hot vehicle or in the sun for weeks, things become suspect.
Plastic water bottles are constructed from such materials as polyethylene terephthalate (PET), which is ever so slightly permeable.
As time passes, and particularly with heating, minute quantities of chemicals from the plastic will seep into the water. You won't notice or even smell these changes, but they exist.
In sufficient quantity or over a period of time, they can be actual health hazards. The science isn't settled about how much is too much, but it's not good.
Then there’s the issue of bacteria if you’ve already taken a sip and left the water bottle around, maybe on your bedside table or inside your reusable bottle. You’ve introduced air, dirty fingers, and maybe even backwash into the mix.
And if the water sits too long in that warm, moist environment? That’s basically an open invitation for bacteria or even mold to move in. This is where genuine public health issues come into play. You may or may not fall ill every time, but why risk it?
There have even been anecdotal accounts of children and adults falling ill after consuming stale water that was left out too long or was stored poorly.
Nothing terribly sensational. Imagine experiencing stomach cramps and nausea, which can occasionally worsen. But still, not really something you want to mess with on a random Tuesday.
Bottom line? Safety in the water isn't just in the water. It's also in the container, including how long it's been sitting there and where it's been stored. If in doubt, dump it out and reach for a new glass.
Signs That Bottled Water Has Gone Bad
Even though bottled water doesn’t spoil like milk or meat, it can go bad in its own quiet, sneaky way. Here’s what to look out for if you’re wondering whether that old water is still safe to drink.
First, trust your instincts. If it tastes off, like plastic or metal, or simply tastes flat and stale, that is your first red flag. When chlorine vaporizes (which occurs in both faucet water and bottled water), the water will no longer have its characteristic "clean" taste. If it smells moldy and chemical? Throw it away.
Then check the bottle itself. If it is swollen, colored, or just a little "off," there's something amiss. A plastic bottle left in the sun or a warm car will warp or deteriorate. That's a sign that chemicals have leaked into your otherwise pure water, making it less refreshing.
Inspect inside. Suspended particles? Cloudiness? Slimey deposit? That can be an indication that bacteria have collected, especially if the seal was broken or the water was exposed to air or contaminated by dirty fingers. Even if it doesn't appear revolting, it's worth playing safe.
And don't forget the expiration date. It's not always a hard stop, but it reminds you how long the water bottle has been sitting around. Water stored in a shaded area and away from heat lasts the longest; however, even the best of storing water habits can't turn it into a fountain of youth.
Last tip? If it doesn't feel right, don't drink it. Use a new glass, fill an empty, clean, refillable container, and stay safe.
How Long Is Bottled Water Safe to Drink After Opening?
If you're curious about how long bottled water is safe to drink after being opened, the rule of thumb is easy: drink it in 2 to 3 days. Provided that you've stored the bottle in a cool, shaded area, and you haven't been drinking straight from the top every day.
That's the thing, though: once that seal is broken, air seeps in. That can cause chlorine to evaporate, imperceptible flavor differences, and ultimately, bacterial growth.
Most of us aren't cracking open a water bottle while wearing gloves. Grubby fingers, a grimy cap, or just leaving it on the bedside table overnight can let all manner of unseen stuff in.
Temperature also makes a significant contribution. When the water is at room temperature, bacteria grow more rapidly. But if you keep bottled water in the refrigerator immediately after opening it, you gain a little extra time and keep the water safer for longer.
Also, consider how you're consuming it. With a clean glass? Fine. Sipping from the same warm bottle in your car over and over again? Not so fine. That back-and-forth between your mouth and the bottle introduces bacteria each time.
If the water tastes funny or smells strange, it's best to discard it and get another one. It just isn't worth risking your health.
And if you're still wondering what happens if you consume old water in a bottle, well, if it's been sitting open for a while and not kept very well, you might get a little ill. Not always, but enough to make you hesitate.
Safe Storage Tips to Extend Bottled Water’s Shelf Life
Do you need your bottled water to stay fresh longer? It's largely a matter of where and how you keep it.
Store your plastic water bottles in a cooler location, out of heat and sunlight. That is not in a hot vehicle, on a windowsill, or near any electronics. Heat accelerates chemical leaching, and eventually, tiny amounts of material from the plastic, such as polyethylene terephthalate, will leach into your drinking water. Not so tasty now, is it?
A dark area, such as a pantry or cabinet, would be perfect. Just ensure that it's not damp and not contaminated by something unpleasant. Yes, water smells, too. Plastic bottles are slightly porous, so even airborne carbon dioxide can ruin the taste and cause you to experience an off or stale taste.
Store bottled water upright. That helps avoid possible contamination from the cap or threads of the bottle, which might collect dust or bacteria over time. If you’re using a reusable bottle, wash it regularly with soap and hot water.
To store water for emergencies, turn your water over every 6 months to a year. Even bottled water purchased from the market has expiration dates, and water that sits around too long, even when properly stored, will eventually taste off or go stale.
It is not a large problem, perhaps, but good water practices preserve your health if bottled water is your sole source of clean drinking water. A little planning now is worth it than to be sick later.
What About Reusing Plastic Bottles?
We've all been guilty of it, finishing off a water bottle and saying, "Ah, I'll just top this one off." It seems like a convenient and less wasteful approach.
However, if you do reuse plastic water bottles, specifically the single-use ones made from polyethylene terephthalate (PET), here are some things you might want to know.
Early on, these bottles were never intended for reuse. With time, and as the plastic itself weakens, particularly if it is exposed to heat or washed repeatedly, it begins to leach infinitesimal amounts of chemicals into your water.
Not a surefire health calamity, but not exactly something to be joked about either.
And then there's the bacteria factor. It's difficult to thoroughly clean these bottles. The tight neck, crevices around the cap, and scratches on the bottle are hideaways for germs.
Dirty fingers, backwash, and exposure to the air? Mini petri dish paradise. Bacteria thrive in warm, moist climates, provided that water is available for a short period.
A safer alternative? Replace the single-use plastics with BPA-free plastic, glass, or stainless steel bottles. They're designed to be reused, are easier to clean, and won't degrade like single-use plastics.
The bottom line: it's okay to refill in a pinch, but make the change on a daily basis. Your water safety (and stomach) will thank you.
Final Verdict: Is It Ever Safe to Drink Old Bottled Water?
Here's the truth: yes, it's possible that old bottled water can be safe to drink, but only if certain conditions are met.
If the bottle is closed, hasn't been left in a hot car, and has been stored in a cool, dark place, the water inside is likely just as good, even if it's beyond the date printed on the container.
The water itself doesn't expire. The problem is the plastic it's kept in and how long it's been sitting there.
However, as soon as the seal is broken or if the water bottle has been contaminated by heat, light, or air, a different situation arises.
That's when bacteria may multiply, chemicals can seep out, and the flavor may degrade. Public health issues arise when water is left standing for too long and begins to change.
Ultimately, it comes down to using common sense. Examine it. Sniff it. Sample a sip. If something does not feel right, do not compel it. Get a new glass or replacement from a fresh source. If unsure, discard it.
Safe drinking is always worth the slight added effort.