Taking a drink bottle around is a great way to stay hydrated whether you are sporty person or not. The big question is: how often is your bottle washed?
It should be washed every day in the dishwasher, or with soap and hot water in the sink. Even if you are doing this regularly, water bottles can still have a musty smell which can taint the water.
We recommend rinsing your bottles in vinegar once a week. This will kill unwanted bacteria, but also has the added benefit of removing any unpleasant musty smells.
All you need to do is clean your bottles in the normal way and then add 1/3 cup vinegar to the bottle. Slosh this about and leave it for about 5 minutes. Clean this out well with water and dry completely. You will avoid lots of nasties that will grow in an unwashed bottle and you will be healthier for the small effort.
Reference: www.cosmopolitan.co.uk: Refilling your water bottle could be as dirty as licking your toilet