What Happens If You Drink Out of the Same Water Glass for a Week, According to Doctors

Even if you do wash your water glass regularly, leaving water sitting out can be problematic, according to all of the doctors we spoke with. "A glass left out in open air may be exposed to airborne bacteria from dust particles or other sources," Trinh explains. 

For that reason alone, keeping a water bottle with a lid on your nightstand might be the best idea. (It will also prevent spills, for the accident-prone among us.)

Whatever container you use for your water, don't forget to replenish it with fresh H2O every day. "Bacteria can also grow in the water if it is not changed often in as little as a few days, so don't leave water uncovered next to your nightstand,"

Stone warns.Drinking plenty of water is great for your body: A recent study linked good hydration habits with living longer and developing fewer chronic health problems. 

Sure, you've got lots of beverage options when you're thirsty (although you may want to skip the diet soda), but water is the best choice you can make for your health. Going even one day without drinking water can result in dizziness, fatigue, digestive problems, and more.

Still, it's important to take precautions when it comes to the way you drink water. One of those, doctors say, is making sure you're not exposing yourself to harmful bacteria and inadvertently raising your risk of illness by drinking out of a dirty glass.