Is It OK to Drink the “Stale” Water You Left Out Overnight?


Quite frequently, we open a bottle of water, drink part of it and leave the rest in the bottle. We don’t really consider the fact that we left a cup or bottle of water unfinished when we get thirsty again, we just drink it. A prime example of this is when we take a glass of water to bed, drink a bit of it and leave the rest. When we wake up thirsty the next morning or in the middle of the night, we drink it without considering that the water isn’t fresh anymore. If asked to actually account for the number of times we have done this, we would be unable to do so because it simply becomes a routine-like action.

In the last one hour, you must have done that, and even I did it last night. Woke up thirsty and grabbed the bottle of unfinished water on my nightstand. I didn’t stop to consider anything but soothing my thirst when I grabbed that bottle so don’t feel bad that you do it. 

It is very normal to wake up feeling hot and thirsty and the burning need to really get some water into our systems. But have we stopped to actually consider if drinking such stale water is good for our health.

What happens to water that has stayed out overnight?

Just like what happens when you leave any edible material such as fruits, wine, and beer outside for a while, the same happens to water, the taste changes. The taste of wine changes, the beer turns sour, and fruits get oxidized and change their flavor.

As for water, long periods of exposure to air would cause changes to occur in its taste and chemical composition. First, the water would absorb more carbon dioxide from the atmosphere to form carbonic acid. This acid affects the overall pH value of the water causing a slight decrease. This slight change in the water pH accounts for the difference in the taste of the water.

In addition to this, tap water from a particular area that contains chlorine as a purification agent can taste different after a period of exposure to air. This is because the chlorine that is added to the water evaporates after a period of exposure to air leaving the water with a somewhat stale taste.

Having known what happens to day-old water, is it okay medically to consume water that had stayed for more than one day or a day.
Well, yes it’s okay to drink it despite the changes and here’s why.

We have ascertained that the water would lose some of its chemicals, form new compounds and lose its taste. But that is not the only thing that can change. There are other factors at play, and some of them include dust, bugs, and dirt. When all or one of these gets into your water, they contaminate the water by releasing some bacteria into it. In addition to all this, our saliva contains bacteria, and since you have already drank from it before, the bacteria would be introduced into the cup.

So why should we still drink this day old water if it is already contaminated? The answer is simple. It won’t hurt you. The chances of you getting hurt by a bacteria that came from your body in the first place is very low. The only way it would prove to be harmful is if the water had been kept for several days in a row. So unless that happens, the worst that could happen is that the water would taste different. 

So don’t be afraid to drink the water in the bottle by your nightstand. The water isn’t going to hurt you or make you sick. You’ll still be as good as new.

Leaving your water in a bottle becomes a problem, and a health hazard when said water is in a plastic covered container which sits directly under the ray of the sun. Plastic bottles are really good at holding certain things such as a dangerous chemical called BPA.

Although the BPA is not something that can easily poison us, even if it does catch a few hours of sunlight, it is very much advisable to get a fresh bottle of water to drink just to be on the safe side.

Another factor to consider is the vessel used to store the water. While the water on its own might not pose a problem to our health, the vessel used for storage be it a glass cup, a plastic bottle or a cup might be a cause for concern. This is mainly because although the water might contain certain bacteria, the vessel used for storage might contain something worse.

You need to know more about what the cup has to do with the safety of water, when to drink water and why we shouldn’t share our water and you can do that by watching the video below.

Are you guilty of drinking the day old water? If you are, let us know in the comment section if you have ever noticed a different taste or any other thing.


About Author