The Surprising Everyday Item That’s Dirtier Than a Toilet Seat, According to One Study

published Apr 7, 2023
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Staying hydrated is an important part of looking and feeling your best. And to meet the recommended daily amount of water (91 to 124 ounces for the average person) many people turn to reusable water bottles. Not only do they make it easier to track how much H2O you’re getting, but it’s also a more environmentally friendly approach to staying on top of your daily water intake without contributing to landfills. 

Unfortunately, many reusable water bottles are harboring a dirty secret: bacteria. According to, the average reusable bottle has 40,000 times the amount of bacteria as a toilet seat. Unfortunately, that’s not the only ick-inducing statistic they had to share.

Water Bottles Are Home to Two Types of Bacteria

Researchers discovered two main types of bacteria on the water bottles they tested: gram-negative rods and bacillus. The gram-negative rod bacteria are rod-shaped and are responsible for causing the types of infections that are often found in healthcare settings, such as pneumonia or meningitis. As if that wasn’t an unsettling enough finding, the researchers at say that these types of bacteria have been known to cause antibiotic-resistant infections. Bacillus, on the other hand, is most commonly associated with food-spoiling and disease-causing bacteria (like endocarditis, bacteremia, and septicemia). 

It turns out that reusable water bottles are hiding an average of 20.8 million CFUs (colony-forming units) of bacteria. To put that in perspective, when they performed the same tests on toilet seats, researchers found just 515 CFUs. 

However, not all water bottles are created the same when it comes to bacteria. Spout-top and screw-top lids both have an average of 30 million CFUs of gram-negative rod bacteria. Straw lids are only slightly cleaner with 20 million CFUs of gram-negative bacteria and 200,000 CFUs of bacillus. Squeeze-top lids appear to have the least, with just 3 million CFUs of gram-negative rods, making it the cleanest option out there. 

Proper Cleaning Can Reduce Bacteria in Water Bottles

Don’t let this news scare you away from reusable water bottles. The truth is that most people likely aren’t cleaning and sanitizing their water bottles enough, especially given how often they’re used. It’s important to make cleaning your water bottles part of your daily routine. 

Ensure your water bottle is getting a thorough cleaning by following this pro-backed cleaning routine, using dish soap, a bottle brush, and some hot water to get into every nook and cranny. Be sure to tackle the removable parts, too. 

This news may be alarming at first glance but keeping hydrated (and keeping disposable water bottles out of landfills) remains a top priority. Following the pro-recommended cleaning routine above will go a long way in helping you stay healthy while accomplishing both of those goals! 

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