Never drink water that has been sitting overnight on your bedside table. Here’s the reason why

Many people have a habit of drinking water first thing in the morning, right after they wake up. You might have even heard your parents or grandparents say that it’s a healthy practice.

And they’re not wrong—starting your day with a glass of water can help kickstart your metabolism, rehydrate your body after a long night, and even improve your focus and energy levels.

But if you’ve been doing this for a while, you’ve probably noticed something: the water you drink in the morning sometimes tastes a little… off. It’s not the same as the fresh, crisp water you’d get straight from the fridge or a clean glass. Why is that?

Well, let’s break it down. If you leave a glass of water on your bedside table overnight, it’s not just sitting there untouched. Over the course of several hours, a lot can happen to that water.

For starters, dust particles from the air can settle into the glass. If your room isn’t completely sealed off, tiny bits of dust, pollen, or even pet dander (if you have pets) can float around and land in your water. Not the most appetizing thought, right?

But that’s not all. The water is also exposed to bacteria in the air. Even in a relatively clean environment, there are always microscopic organisms floating around. When they land in your glass, they can start to multiply, especially if the room is warm.

This doesn’t necessarily mean the water is dangerous to drink, but it can definitely affect the taste.

Now, let’s talk about the science behind the taste change. When water is left out in the open, it doesn’t just sit there passively. It actually interacts with the air around it. One of the key things that happens is that the water absorbs carbon dioxide (CO2) from the air. When CO2 dissolves in water, it forms a weak acid called carbonic acid.

This chemical reaction changes the composition of the water slightly, lowering its pH level and making it a bit more acidic.

Over time, this carbonic acid can break down further, releasing protons that turn into carbonate or bicarbonate ions. This process is what gives the water that slightly flat or stale taste you might notice in the morning.

So, to sum it up: the water isn’t necessarily “bad” or harmful after sitting out all night, but it’s definitely not as fresh as it was when you first poured it.

It’s picked up dust, bacteria, and undergone a subtle chemical change that alters its taste. If you’re someone who’s sensitive to flavors, you’ll probably notice the difference right away.

What can you do about it? If you still want to keep up your morning hydration habit (which is a great idea!), consider using a covered water bottle or a glass with a lid to keep out dust and bacteria. Or, simply pour yourself a fresh glass of water in the morning instead of drinking from the one that’s been sitting out all night. That way, you can enjoy the health benefits of morning hydration without the weird aftertaste!