Personally, I think it’s weird to have a piece of drinkware that you don’t think needs to be washed.

I mean sure, it only holds water but your mouth goes on there (and if you have kids, stuff besides water definitely ends up inside that straw and cup).

If you’re with me and wash your reusable water bottle semi-regularly, you can consider yourself vindicated – because we’re definitely in the right.

Up to 60% of Americans own at least one (likely more) reusable water bottle. We want to do our part for the environment, and now that we read science, we also understand the importance of staying hydrated.

That said, around 15% of people don’t ever wash theirs, and another large chunk of people don’t wash their bottles nearly often enough.

And they definitely should, since they harbor a whole bunch of microbes, including bacteria, viruses, and fungi that could make them sick. Your mouth makes contact with the bottle and/or straw every time you take a sip, transferring food, bodily fluids, and whatever else is stuck in or around your mouth and lips.

Once those things get inside the bottle, they absolutely thrive in the continuously damp environment.

This 2017 study found that nearly every water bottle they tested contained bacteria. 70% of them contained more than what some countries allow in public drinking water, and 60% of them were so contaminated they exceeded even the most lax safety limits.

It was a small study, but still. ick.

Around 25% of the bottles also contained coliform bacteria that are linked to foodborne illnesses that were likely to pose a serious health risk to anyone who used them.

Glass bottles had the lowest levels of contamination, and those that were used for beverages other than water had the highest, likely because of the sugar content in those other drinks.

The same study found that while 84% of people do clean their water bottles, most weren’t doing a good enough job. A shocking 15% never cleaned their bottles, and only 46% of people at least rinsed theirs daily.

A quick rinse is better than nothing, but it’s not going to do the same job as a real cleaning – not if you really want to get rid of the potential threats. According to a different study, the average reusable bottle contains around 75,000 bacteria per milliliter of liquid, but if you let it sit for 24 hours, that number multiplies to 2 million.

In order to combat that kind of environment and growth you’ll need to was the inside, outside, crevices, seals, straws, and any other removable part with hot water and dish soap, and make sure you’re thorough about it, too.

Some experts say it doesn’t hurt to wipe the whole thing down with a food-grade anti-microbial wipe when you’re done, too.

Either way, get those bottles in some soapy water, asap.

You don’t have to admit how long it’s been since the last time, just get it done!

If you found that story interesting, learn more about why people often wake up around 3 AM and keep doing it for life.