You’ve got a water glass in the bathroom, at your desk, and on your nightstand, which means you’re chugging plenty of H20 (high-five for hydration and props for passing on plastic!).
But with all the focus on getting the recommended 8 cups a day, some of those glasses have gone unwashed for days—you just keep dumping them out and filling them up.
What will probably happen: A whole lotta nothing, especially if you’re the only one using the glass. “It’s important to mention that pathogens—those organisms that make you sick—don’t just appear out of nowhere; they have to be introduced by someone or something,” says Margolin. The fact that it’s a glass, not a plastic cup, means it won’t degrade over time, creating nooks and crannies where bacteria can build up. Plus, glass is more likely to completely dry, and drying, also known as desiccation, is an excellent way to halt the growth of bacteria, adds Margolin. What’s more, if you’re filling up with tap water, most treatment plants use chlorine to zap dangerous contaminants that work both on the water and your saliva.
“If you restrict the usage of the cup to a single individual and you make sure that the water is clean, then you are not going to get sick if you use the same cup over and over,” says Margolin.