There is a high chance that you have gulped down water from a water bottle or cup left over from the previous night— be it on the nighttable, on the counter, in the car—but how safe is it to drink stale water?
You probably know that drinking water left in an open glass is not super hygienic. Dust, debris, and even the odd passing mosquito, can drop into the glass overnight, leaving an unhealthy surface scum.
As it turns out, even a closed container like a bottle introduces problems, mainly because our skin is coated with sweat, dust, skin cells, and even nasal discharge, so once we put the bottle in our mouth, these can all “backwash” into the remaining water, causing contamination.
Furthermore, our saliva also carries bacteria, which does the same. If it’s allowed to incubate for hours, that could potentially contaminate the water, and make you ill by reintroducing that bacteria. Once you have put your lips to the bottle, you should consume that bottle in one sitting and then discard it.
Since it’s your own bacteria however, it’s unlikely that you’ll actually get sick. While no one brags about it, a lot of people sip from used drinking glasses, mugs, and bottles without any ill effects.
It isn’t advisable to share your bottle with someone else. Neither should someone with a reduced immune system, such as transplant patients, those undergoing chemotherapy, or people living with HIV/AIDS, be exposed to contaminated water.
You should also know that it makes no difference whether it’s bottled or tap water. Both have to meet exacting hygiene standards, and up to 25 percent of bottled water is drawn from the main water supply anyway.
More so, water left in the sun will heat up, making it the perfect breeding ground for bacteria, especially if you’ve already drunk from it. Placing the bottle under your seat may reduce the heat a little, but bacteria will still grow.
Some kinds of plastic bottles contain BPA or similar chemicals, which can leach into the water, especially when it’s exposed to sunlight. There is research suggesting that BPA could be linked to health problems affecting the brain and behaviour.
Using a BPA-free bottle would eliminate this issue, but not the growth of bacteria, especially if you’re using a metal bottle, which heats up quickly, encouraging the germs to multiply.
Avoid putting your mouth to the bottle. Just pour it into a cup or pour it directly into your mouth to stay healthy always.