How Often You Should Clean Your Water Bottle Straw, According To Experts

Whether at work, at the gym, at school or simply out running errands, most people carry around reusable water bottles to help them stay hydrated throughout the day. But most people don’t wash them as often as they’d wash a bowl or cup after using it. The thought is, if it’s only holding water, how dirty can it be?

“There’s been studies that have shown that these reusable water bottles can carry actually more bacteria than common items that may be in your household, like kitchen sponges or even dog bowls,” said Dr. Chirag Panchal, a family medicine doctor with Orlando Health in Florida. “So, that’s why cleaning them regularly is just so important.”

This is true for the water bottle, and also any accessories that come with it, such as the reusable straws that are now commonly a package deal with the bottle. Think about it: your mouth goes right on the straw and any backwash (sorry) goes down the straw.

You should keep a few things in mind when it comes to reusable water bottle straw cleanliness. Here’s what to know:

Just because you put your mouth directly on the water bottle straw doesn’t mean it’s any dirtier than your water bottle. Instead, both get pretty grimy.

“We sampled personal water bottles from students walking around campus … they get tons of bacteria because every time you drink, use the straw or drink out of the regular water bottle, a little bit of saliva gets back into the water, which is great food for the bacteria,” said Dr. Charles Gerba, a professor of virology at the University of Arizona.

If you don’t wash your straw often, bacteria builds up. Gerba recommends that you wash your reusable straw and water bottle at least once a week.

Panchal thinks you should wash your water bottle and straw a little more often than that, and recommends committing to doing it daily.

If you don’t wash the straw and bottle regularly, bacteria will grow and coat the straw and the water bottle with a biofilm, Gerba said. A biofilm is “where bacteria grow and habitate,” he said. Biofilm can create odors and bad tastes in your water bottle or straw.

“Reusable water bottles are safe, and they’re very effective at getting us hydrated and reminding us to be hydrated, but they’re hot spots for bacteria, so they should be cleaned regularly,” Panchal said.

If you are using it for drinks other than water, whether lemonade, iced coffee or a sports drink, it should be washed after each use, not just once a day.

“It doesn’t take long to put some warm, soapy water in there and slosh things around and then give it a good rinse and let it dry,” said Matthew Fields, the director of the Center for Biofilm Engineering at Montana State University.

Panchal recommends that drinkers use proper bottle-cleaning brushes and straw-cleaning brushes when washing their water bottles.

And it is important that you let the bottle fully dry with the cap off if you aren’t going to use it right away, Fields noted.

If you put the water bottle top on while there are still a few drops of water in there, “that’s not sterile,” Fields said. “Any time where there’s moisture, microbes could then start to grow back.”

The bacteria in your water bottle is your own bacteria, so it could make you sick, but that is not the most likely scenario.

“Poor cleaning habits could lead to things like bad breath, unpleasant odors,” Panchal explained. “Even stomach illnesses and infections, because your water bottles are carrying and growing bacteria if they’re not washed, so it can negatively impact your health if you don’t clean them regularly.”

You shouldn’t use the water in the bottle to wet your finger for a contact lens or to clean out a cut, according to Gerba, because of the amount of bacteria typically in one of these canisters.

Again, since a water bottle is loaded with the water bottle owner’s bacteria, “you should never share a water bottle with anybody ever,” Gerba stressed. “These water bottles are loaded with anything that was in your mouth … and often growing to large numbers, believe it or not.”

So, if you’re out with a friend and suddenly get thirsty, it’s best to buy yourself something to drink instead of asking for a sip of their beverage.

“Their bacteria are growing in there, they may have bacteria that can make you ill,” he said.

The risk is moderate, but if your friend has a sore throat, you could end up taking a sip from their water bottle and get that sore-throat-causing bacteria, too, Gerba noted.

Some water bottles are known to be harder to clean than others. Bottles with lots of crevices or angles are harder to properly wash, Panchal noted.

“The trendier-looking water bottles may not always be the best because when we’re looking for something that’s easy to clean, we want it to have removable pieces, large, wide mouth areas,” Panchal said.

You also want a bottle that has a smooth interior finish because, once again, “hard angles can be tough to clean,” he added.