If you have ever left a glass of water overnight and drank it the next day, have you noticed it doesn’t taste the same? This odd taste may be indicative that the water has gone bad. This brings us to this all-important question: “Did You Know That Water Left Overnight In A Glass Is Bad For You?” Below, a microbiologist gives us the information we need.


Glass of Water Left Overnight Is Bad For You



Introducing Microbes

For starters, dust accumulates in the glass, in addition to microbes, although the latter isn’t the cause of the stale taste. Instead, the water exposed to air absorbs carbon dioxide. Part of the carbon dioxide converts into carbonic acid, which changes its chemical composition. Furthermore, it releases protons that transform into either carbonate or bicarbonate. As such, the water’s pH value changes, thereby changing its taste. Simply put, if water has been sitting out exposed to air for too long, it is the equivalent of mild acid rain.

Additionally, drinking water from a glass causes microbes to be introduced into the water from the mouth, the lips, and of course the saliva. The microbes then multiply in mild temperature environments. So, the warmer the room, the greater the microbes in the water. And, the colder the room, the longer the water will maintain its chemical composition and keep.

Chlorine compounds are also added to both bottled water and tap water to ensure microorganisms are kept away. The environmental microbiologist, Kellogg Schwab, states that these chemicals only remain in the water for up to two days.

According to Schwab, the expert at John Hopkins University, a day-old water in a glass is safe to drink. However, it is crucial to avoid reusing a glass. Furthermore, do not touch the rim of the glass nor share glasses with others.

While day-old water and water exposed to air for extended periods of time has been explained, it is a good question to ask what about sealed bottled water? Because it is sealed, bottled water will not go bad. But, always check the expiration date.

Source: SmithonianMag.com