science of us

How Often Should I Wash My Office Water Bottle?

Clean me. Photo: Lee Jeong Jin/Getty Images/iStockphoto

The other day I was wondering how clean I should be keeping my office drinking vessels. According to an earlier story, it’s fine to never wash office coffee mugs, which is both satisfying and unsettling. But is it true?

The simple answer, says Susan Whittier, director of Columbia University’s Clinical Microbiology Lab, is no: “Water bottles and coffee mugs should be cleaned with soap and water at the end of each day,” she told me, “just like you would do at home.”

She also outlined some potential office hazards I hadn’t considered:

Depending on how “open” your work space is, I might also recommend cleaning the mugs and bottles during the day, too. Are there a lot of people passing by, coughing and sneezing? The chance of an infectious disease being transferred from one person to another is minimal, but people are “grossed out” by the thought of other people’s germs in their containers! And are there water-damaged ceiling tiles above you, which are a common source of mold that can contaminate the environment?

Well, that’s terrible to think about, although fortunately New York Magazine has a nice ceiling.

I was also curious to hear Whittier’s take on the dangers of communal office sponges, which I understand can be especially foul.

“I am not a fan of communal office sponges,” Whittier said, noting that perpetually moist sponges are especially fertile breeding grounds for bacteria, and that we never know what a shared sponge might have been used for beforehand — “or how well it was cleaned.”

As an alternative to the shared office sponge (and to never washing your mugs and water bottles at all), Whittier recommends using a clean paper towel, with soap and water.

Also, if your office water bottle has a lid, her suggestion is to keep it on as much as possible, to protect against the crumbling, moldy ceiling panels you might work beneath and the infectious co-workers strolling past your desk — although nothing can protect you from yourself, i.e. your own bacteria and (possibly) viruses: “As you drink from your water bottle all day, your own germs are being transferred,” Whittier said. “Again, typically not a big deal but if you’re sick you can potentially keep reinfecting yourself.”

How Often Should I Wash My Office Water Bottle?