Because you really don't want to set yourself up for E. coli, right? Right. We’re spilling our secrets for keeping reusable water bottles clean.

By Isadora Baum
Photo by Carson Downing

That trusty reusable water bottle you carry with you keeps you healthy and hydrated, but only if it’s clean. And let's face it: Most of us don’t think to clean out our water bottles. More often than not, we take that last sip (on our quest to drink more water, natch), refill it, and sip some more—on repeat.

Whether your water bottle is stainless steel, plastic, or made from another hard material, it’s important to sanitize it at the end of each day to prevent water bottle bacteria. “Since it’s a moist environment, it's possible for bacteria to set up shop and thrive, potentially leading to symptoms such as nausea, vomiting, and diarrhea,” says Robert Glatter, M.D., an assistant professor of emergency medicine at Northwell Health in New Hyde Park, New York and attending emergency physician at Lenox Hill Hospital.

Give the cap, as well as the straw if your bottle has one, a good cleaning too. “Bacteria such as E. coli that lead to gastroenteritis and food poisoning and even molds could colonize this area,” he says. You can even take a step further and scrub this area with a special bottle brush or toothbrush for a real deep clean and a better chance at a bacteria-free water bottle. Or just get in the habit of using one of these five simple and easy methods for keeping reusable water bottles clean. 

The Dishwasher

Many types of water bottles are dishwasher safe, but check that it says so on the bottle first. “Place bottle and top in the top rack, making sure that the bottle does not interfere with the spray arms if your model has them at the top,” says Donna Smallin Kuper, IICRC-certified house cleaning technician and author of Cleaning Plain & Simple. Then, run the dishwasher with the hottest water settings and a heated dry cycle, which will kill water bottle bacteria. It should be totally dry before you reuse it; moisture can be a breeding ground for bugs. (Really, healthy Is your home?)

Soap and Water

Keeping reusable water bottles clean is possible with simply washing by hand with a sudsy mix of dishwashing liquid and hot water, Kuper says. Be sure to wash and dry off with a clean cloth (or paper towel) to avoid reintroducing any bacteria or other harmful water bottle bacteria. Swish the soapy water through the entire bottle, the same way as you'd wash out a coffee cup or other used glass or mug, and make sure you get rid of any gunky buildup on the bottom or by the cap area. Then rinse with water to remove any soap residue before drying.


That bottle of vinegar in your pantry (one of our top chemical-free cleaning agents) can also disinfect your water bottle. “You can also use dilute vinegar, which helps to kill most bacteria (not viruses though), while also serving as a drying agent,” says Dr. Glatter. “Fill half of the bottle with white vinegar, the other half with water,” he says. (Make sure you use about ¼ cup of vinegar.) Close the bottle and let it swish around before leaving it to soak to banish the bacteria found in reusable water bottles. Let it sit overnight and rinse out in the morning.

3 Percent Hydrogen Peroxide

If the inside of the bottle is kind of slimy or has an odor, you might want to step up your water bottle bacteria strategy with this method. “This is my preferred method for disinfecting. Clean the bottle and top thoroughly with soap and water and rinse with hot water. Then pour about ¼ cup of hydrogen peroxide in the bottle, replace, and close the lid tightly,” says Kuper. Shake the bottle vigorously, then pour out the hydrogen peroxide, and give it a final water rinse to make sure it’s all gone. Your bottle should now be sparkly clean. (Score 48 more helpful hydration tips.)

Water Cleaning Tablets

“Water cleaning tablets are another reasonable approach, as well as tablets used to clean dentures,” says Dr. Glatter. It’s a super easy fix for how to clean water bottles. (P.S. These 6 new bottled waters are making a splash.) Fill your bottle with water, drop the tablets in as directed on the package, and let it sit for at least 30 minutes. Then simply rinse out your bottle, and you're good to go.

This story originally appeared on Health.