Is it safe to drink water that’s been sitting overnight

We all have the experience of preparing a glass of water beside the bed that’s been sitting out overnight, just in case we may wake up at 5 a.m., feeling like some water because of the binge the night before. But usually, instead of fresh and crisp, that water tastes weird. Why does the flavor change? Let me explain why.

What makes it taste stale?

If it is tap water, the chlorin added in it may gradually evaporate during those hours, which can change the flavor. Besides, after being left out for several hours, carbon dioxide in the air can interact with the water in the glass, thus lowering its PH level and giving it an off-taste.

What else happens to water overnight?

Firstly, when you leave the glass of water on the table, it is actually collecting debris like dust. Surface scum on your glass could combine with these microorganisms that could make you sick. However, if you clean the glass every day, and don’t share it with others, you won’t have any problems –unless the rim of the glass was touched by dirty hands, which went unwashed after using the bathroom, for example.

Another thing that will happen when you leave the water overnight is, “backwash”. Because our skin is coated with sweat, dust, skin cells, and even nasal discharge, when we drink water, this stuff will “backwash” into the remaining water, thus causing contamination. Our saliva also contains bacteria, so it could do the same thing. According to scientists, the best practice is to consume the glass of water in one sitting and not leave it for hours.

Could you get sick drinking day-old water?

Since it’s your own bacteria, drinking day-old water won’t make you sick. And because water contains no sugars, fats, or proteins that may go rot, it doesn’t go bad after sitting out for hours despite the weird flavor.

The important thing to remember: don’t reuse the same glass forever without washing it, or share it with others especially those who have relatively weak immunity. Also, you should wash your hands each time you have used the bathroom in case the microorganisms or bacteria are transmitted to the water.