According to research from the website Treadmillreviews, refilling your water bottle without washing it is just as dirty as licking a toilet seat.
You fill a bottle with water, so you may have the feeling that it stays clean by itself. So that's not true.
Lots of bacteria
Researchers test various reusable bottles. The bottles were all used by an athlete for a week. The vial with the highest bacterial count contained more than 900,000 CFU per square centimeter. That is more than on a toilet seat… An average bottle contains 313,499 CFU, still very much.
Don't throw away your water bottles right away Drinking enough water is good for you and a refillable bottle is a cheap and environmentally friendly option. Clean your bottle every day and make sure that it is easy to clean when buying. Inaccessible corners are a no go.
There is a lot of difference between different caps. A cap with a straw contains the least bacteria. It is better to leave the sliding cap for what it is.
3 more reasons not to drink water from a bottle.