The bristles are abrasive, knocking loose any physical buildup while delivering dish soap into the hardest-to-reach nooks of my Nalgene. With the bottle itself clean, I simply scrub the cap with a soapy sponge, rinse thoroughly with hot water, and let it all air dry. (If your lid has a built-in straw, it’s probably a good idea to pick up a straw brush as well.) When I'm done, I simply toss the cleaning brush in the dishwasher so it’s nice and sterile for my next water bottle cleaning session.
Drinking Straw Cleaning Brushes
Brushing with soapy water is the cleaning method that works for me, but there are additional steps you can take to keep your bottle sparkling. To combat mineral build-up and off smells, I picked up a box of these fizzy cleaning tablets. To use them, simply fill your bottle with water, plop in a tablet, let it sit for at least 30 minutes or up to overnight, rinse it out, and you’re good to go.
While there’s no replacement for a tough scrub to take out tougher grime and debris, these tablets do a great job of getting rid of unpleasant lingering smells—especially if you give them a couple hours to work their magic. They’re an especially good choice for CamelBak backpacks, whose long, winding straws, mouthpiece, and tight crevices are notoriously difficult to clean. They’re also great for Hydro Flasks since it’s harder to spot mildew in a stainless steel water bottle than through transparent plastic.
The biggest thing these tablets have going for them is ease of use. Not only do they leave things tasting fresh, but a cursory glance at the ingredients list will reveal plenty of heavy hitting neutral cleaning products like baking soda and hydrogen peroxide (a combo that we recommend to clean your crustiest baking sheets too). They’re also chlorine-free, which means no lingering swimming pool taste. Pick up a box and use once per month for clean water bottles without the elbow grease.
While those tablets are convenient, you can also combine the baking soda you have in your pantry with food-grade hydrogen peroxide if you’d rather DIY it. This duo is so good at cleaning that I use it for everything from pots and pans to my teeth, with shiny, sparkling results all around. For a 1-liter water bottle, add a tablespoon of each, fill with water, leave overnight, and rinse.
For a less intense but still effective way to give your reusable bottle a thorough cleaning, fill it with equal parts white vinegar and warm water and leave it to soak overnight. The next day, rinse the bottle out, give it a soapy scrub with your brush to ensure there’s no lingering vinegar taste, and be on your way.
That depends on a few factors. While most Nalgenes and Hydro Flasks are dishwasher-safe, you should still check the product details for your specific water bottle before throwing it in with last night’s dishes—especially if it’s made of plastic, which can melt and may contain BPAs. If the manufacturer gives you the go ahead, you should still place it on the top rack, where temperatures are lower and there’s less risk of the cap or other small parts going missing.
Still, even if your water bottle is dishwasher safe, you may still want to clean it by hand. I for one have an obnoxious number of stickers on my Nalgene (picture the bumper of your crunchy aunt’s Prius), and a few of them have faded or torn when I’ve put my bottle through the machine. Also, if you use a bottle with a sealing ring on the cap, bacteria and fungus might be able to hide underneath the rubber (which could also be compromised in the dishwasher). Taking the ring off and getting in there with dishwashing liquid and a sponge or a brush will be your best bet for truly eradicating the nasty stuff.
Reusable water bottles are better for the environment. Check! And they're way more stylish than plastic bottles. Check! And they're good for your health and hydration. Check—well, if you know how to clean a water bottle correctly, that is.
If your water bottle is dishwasher-safe (check the label for care instructions), place it on the top rack of the dishwasher and choose the hottest water setting. If not, you can clean a water bottle (and those reusable straws, too!) in less than five minutes. Just follow the simple steps outlined in one of the methods below.
Considerations Before You Get Started
While keeping a reusable water bottle close at hand during work and at the gym is an easy way to stay hydrated, if you fail to clean your water bottle, it could expose you to germs. The inside of a bottle is just the sort of damp, dark environment where bacteria love to grow, making it a perfect breeding ground for mold to proliferate.
In a 2022 study, when researchers tested water bottles for bacteria, they found that the average reusable water bottle contained 40,000 times more bacteria than a toilet seat. Even more troubling, that same study found that about 25 percent of Americans wash their water bottles only a few times a week. And nearly 15 percent of Americans clean their water bottles only a few times a month.
Most Unsanitary Water Bottle Types
When it comes to collecting germs, not all reusable water bottles are alike. In a 2019 study, researchers tested the germ count on four types of reusable water bottles: slide top, squeeze top, straw top, and screw top.
They found that "the squeeze-top bottles had the most germs, with 99 percent harmful bacteria and 1 percent of bacteria that causes strep and staph. Screw-top bottles were the second grossest, with 98 percent harmful bacteria and about 2 percent of harmless bacteria." The study also found that straw tops were the least germy, with "8 percent of bacteria causing strep and staph and 92 percent of harmless bacteria."
How Often to Clean a Water Bottle
If you can see a slimy gloss or smell a bad odor, your water bottle needs cleaning ASAP. The ideal frequency to wash your water bottle is daily if you use it regularly, and give it a deep cleaning once a week. If you're sick, or you've left the water bottle on the floor in a hot, sweat-filled gym or outside, clean it even more frequently.