We Asked Experts About How Many Days Can Pass Without Washing Your Reusable Water Bottle — And Their Answer Was Surprising

I regularly rinse my gym water bottle with some water before refilling it again for another day, but I sometimes worry about how gross this habit is.

When I asked experts about how long I can safely go without properly cleaning my water bottle, they were pragmatic but firm. You don’t need to clean your water bottle with soap and water after every single use ― but there’s a tipping point when simply rinsing with water is no longer safe for your health.

Microbiologist Jason Tetro aka “The Germ Guy,” said three days is his recommended limit for rinsing his water bottle with just water.

“After three days, you should be rinsing with soap and water,” Tetro said. And “by the time you get to five days, you better be scrubbing that down.”

It’s not the water that’s the problem, but your saliva, because that’s “basically food for bacteria,” said Chuck Gerba, a microbiologist at the University of Arizona.