Study Finds Reusable Water Bottles Hold More Bacteria Than Toilet Seats

From a sustainability aspect, reusable water bottles have been a trend for several years now. But, through apps like TikTok and Instagram, the plastic bottle alternatives have also developed a more personal stake for users, as the “emotional support water bottle” trend took over the internet. Despite our love for our favorite reusable water bottles—Yetis, Hydroflasks, Stanley Cups, you name it—a recent study found that, without proper care, these steadfast friends can harbor more germs than a toilet seat.

U.S.-based site, waterfilterguru.com, published a study recently that revealed that reusable water bottles can carry up to 40,000 times more bacteria than the average toilet seat. To collect such data, researchers swabbed the spout lid, straw lid and squeeze-top lid parts of different water bottle three times each, and found gram-negative rods and bacillus bacteria present throughout. Alarmingly, gram-negative bacteria can cause infections that are resistant to antibiotics and certain types of bacillus bacteria can cause gastrointestinal issues.

Not only did the study show that these portable water bottles can harbor 40,000 times as much bacteria as a toilet seat, it also revealed that these bottles can accumulate twice as many germs as the average kitchen sink and 14 times as many germs as your pet’s drinking bowl. Imperial College London molecular microbiologist, Andrew Edwards, explains that “the human mouth is home to a large number and range of different bacteria,” so it’s no surprise that these bottle can serve as a breeding ground for so many germs.

Not to worry, University of Reading microbiologist, Simon Clarke, reassures readers that though reusable water bottles can accumulate a lot of germs “it’s not necessarily dangerous,” as most of the bacteria found in these bottles are from germs already in the users’ mouth. To keep your bottles clean, though, experts recommend washing them at least once a day with hot water and soap and sanitizing it at least once a week, but increasing the practice if you’ve been recently ill or put liquids other than water in the bottle.