We think we’re doing the right thing by always having a bottle of water with us to refill so we stay hydrated and healthy. But it turns out getting the recommended amount of water can have a downside if you’re reusing a plastic bottle.

Treadmillreviews tested refilled water bottles that an athlete had used for a week and they discovered some super gross facts. Their numbers showed that one container had more bacteria on it than the average toilet seat. And as if that’s not bad enough, researchers found that 60% of the germs they found were capable of making you sick. So that might explain why you’ve been feeling under the weather recently.

But there are easy ways to avoid this nastiness. For one thing, you can swap your slide-top bottles for squeeze or screw-top versions. The slide ones have over 933,000 germs per square centimeter and the others have a considerably less scary 160,000. Or just invest in one of those fancy stainless steel bottles that you can wash in the dishwasher. That way you don’t have to live in fear of of all that bacteria.

So keep drinking water, just make sure you’re washing your water bottles more often, no matter what kind they are. You can’t unknow how filthy they really are.

Source: Cosmopolitan