What comes to mind when thinking of the most germ-filled item in your home? While most would say their toilet bowl, a new study reveals a shocking discovery. The item you depend on daily to stay hydrated, while working from home or on the go is dirtier than a toilet bowl. If you guessed a reusable water bottle, you’re right.

Reusable water bottles have become popular for helping health-conscious millennials track their water intake, while doing their part to protect Mother Earth. These water bottles are eco-friendly, but can also have an alarming amount of bacteria. According to a study by WaterFilterGuru.com, the average reusable bottle has 40,000 times more bacteria than a toilet seat.

While this news is surprising, it’s not the only shocking find from the study. Some of the key results from the study reveal that almost 15 percent of Americans clean their water bottle a few times a month, there are 6,000 times more bacteria in a squeeze-top water bottle than in a toilet bowl. The most bacteria of all of the water bottles tested have spout-top and screw-top lids.

Two main types of bacteria found on the water bottles were tested in this study. The first kind is gram-negative rod bacteria and causes infections, such as meningitis, pneumonia and antibiotic-resistant infections. The second kind is bacillus, which is can make antibiotics, but features disease-causing and food-spoiling bacteria.

It may be scary to hear about the high number of bacteria on reusable water bottles, but it can be avoided if you regularly clean them. You should make cleaning your water bottle part of your daily routine. Properly wash your water bottle by using a bristle brush, dish soap and hot water to get in every ridge of your bottle. It’s especially important to clean the inside of your bottle and the parts where you put your mouth. Don’t forget to thoroughly wash the removable parts of your water bottle as well.

Remember that moist items are breeding grounds for bacteria. Staying healthy and hydrated means that you should be washing your reusable water bottle daily.