Do you refill your water bottle every day and take it to work or the gym? If you do, you probably wash it once a week or so, right? A new study tested people's water bottles after they drank out of them for a week at the gym, and they found a HIGH amount of bacteria.The average bottle had 313,000 bacteria colony forming units per square centimeter. That's about 100,000 times more than your toilet seat. And it's six times less sanitary than drinking out of your dog's water bowl.

The researchers say it's because your water bottle is the perfect damp, hot environment for bacteria to grow and thrive. So if you are going to drink out of a reusable bottle, swap it out after a days use.