We love using our Hydro Flasks for everything: water, tea, coffee, juice, smoothies, electrolytes… you name it.
But with all these different drinks comes the need to pay a little extra attention to cleaning, so we can avoid any funky smells, mold, or bacteria building up.
And while you technically could toss your Hydro Flask in the dishwasher and hope for the best, I like to hand wash mine just to be sure it’s spotless.
If you’re with me on wanting full control over the process, then this guide is for you. I’ll walk you through a few simple steps to make sure your Hydro Flask stays in top shape.
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Step #1: Rinse Immediately After Use
One of the simplest yet most effective ways to keep your Hydro Flask clean and odor-free is to rinse it immediately after each use. This prevents leftover liquids from drying up, which can cause stains, odors, or even bacterial growth over time.
Hydro Flasks have a great advantage not to retain odors as much as other bottles, but it’s still worth rinsing it immediately.
I like to take it up a notch by closing the lid and giving the bottle a good shake to loosen any leftover particles. Swirling the water around can also help reach all areas inside the bottle.
Step #2: Wash with Dish Soap
Now it’s time to roll up your sleeves. Start by filling your Hydro Flask halfway with warm water.
Warm water is key here because it works better at breaking down oils, stains, and bacteria than cold water, so don’t skip this step.
Next, add just a few drops of mild dish soap.
At the same time, I stay away from harsh detergents or bleach. These can damage the stainless steel and leave your bottle tasting bad.
Now, grab a bottle brush if you’ve got one. If not, a soft sponge will do, but only if you’re working with a wide-mouth Hydro Flask. Trying to use a sponge for a narrow-mouth is quite challenging.
Scrub the bottom, the sides, and especially the inside of the neck.
Step #3: Take Care of the Cap
I tend to clean the lids, caps, straws, and spouts separately, mainly because they can be a breeding ground for bacteria and mold if not given enough attention.
Just a bit of warm water and soap does the job here, too.
What really helps, though, is using a small brush. It’s much more effective than a sponge for getting into the tight spots, especially around the Hydro Flask Flex Cap. If you don’t have one yet, I’d definitely recommend picking one up from here.
Step #4: Rinse Thoroughly
Make sure to rinse out all soap to avoid any soapy aftertaste.
Step #5: Let It Dry Out
One common mistake I see with Hydro Flask owners is washing it and then immediately closing the cap.
The problem with this approach is that bacteria love moisture, and that’s exactly what you’re giving it when you seal the lid while it’s still damp.
Personally, I always leave the lid off when I’m not using my bottle. This helps prevent any moisture from building up, which in turn keeps odors from settling in.
If you’re short on time and want to speed up the drying process, just grab a paper towel and give the inside a quick wipe.
Step #6: Disinfect Your Hydro Flask (Once a Week)
If you’re cleaning your Hydro Flask daily, that should be enough to keep it fresh and safe to drink from.
But there are a few situations where you might want to clean it more thoroughly:
- If you’ve skipped a few days of cleaning, especially after using it for things like coffee, tea, juice, or protein shakes
- If you notice a bad smell or strange taste
- If you’ve been sick
- If you spot any mold or black spots
- If you’ve been storing it with the lid on for too long
In these cases, it’s a good idea to disinfect your bottle to make sure it’s completely clean.
Here’s how I tackle it:
- Fill the bottle about a quarter full with white vinegar.
- Swirl it around to coat the inside, then let it sit for 5-10 minutes. If the odor is really strong, you can let it soak for a few hours or even overnight, but I’d recommend diluting the vinegar with water (a 1:1 ratio) to protect the stainless steel.
- Fill the rest with warm water and let it soak for another 15-30 minutes or, for a deep clean, let it sit overnight.
- Scrub with a bottle brush, then rinse it thoroughly with warm water.
- Finally, let it air dry upside down with the lid off.
This extra step will help keep your Hydro Flask in top shape when it needs a little more than just the usual cleaning routine.
How Often Should I Wash a Hydro Flask?
The best advice is to wash your Hydro Flask daily when you should rinse it with warm, soapy water and scrub with a bottle brush. In fact, only 42% Americans clean their water bottles every day.
Also, remember about deep cleaning/disinfecting your bottle once a week using white vinegar to remove odors and bacteria buildup.
How Long Can Water Sit in a Hydro Flask?
Water can safely sit in a Hydro Flask for up to 24 hours before it’s best to refresh it. Water left for more than a day may taste stale due to oxygen loss.
But it’s not only about the freshness of your water, but also bacteria growth. While stainless steel resists bacteria, germs can develop over time, especially if you drink directly from the bottle.
What Happens If I Don’t Clean My Hydro Flask?
If you don’t clean your Hydro Flask regularly, you’re basically giving bacteria and mold a free Airbnb inside your bottle.
Over time, funky smells, weird tastes, and even a slimy film (sounds gross because it is) can build up. Sure, it’s “just water”, but even that can get stale and weird if left sitting too long.
Why Does My Hydro Flask Smell Bad After Cleaning?
If your Hydro Flask still smells funky after cleaning, there’s a good chance some bacteria or residue is stubbornly hanging on, especially in the lid, straw, or those sneaky little crevices.
Soap alone doesn’t always cut it, and lingering odors from coffee, tea, or other drinks can cling to the stainless steel.
Try a deep clean with white vinegar disinfecting process I described before to kick the stink for good.
And don’t forget to let it air dry completely. Trapping moisture inside is basically sending mold an invitation.
Is Hydro Flask Dishwasher-Safe?
If you own a Hydro Flask and are wondering whether it can go in the dishwasher, it depends on when you bought it.
If you got yours after 2020, you’re in the clear. These newer models are built to handle the heat. But older versions were made differently, and running them through the dishwasher isn’t a great idea.
Not sure when you bought yours? There’s an easy way to check. Just take a look at the logo. If there’s a little “®” (trademark) symbol next to it, your bottle is from the pre-2020 era and should be washed by hand. No symbol? That means you have one of the updated, dishwasher-safe models.
There’s also a different version of the Hydro Flask called the Trail Series. This one is built a little differently from the standard models and is not dishwasher-safe. If you have a Trail Series bottle, it’s best to wash it by hand.
Can You Clean a Hydro Flask with Boiling Water?
Yes, you can clean your Hydro Flask by pouring boiling water into it, although with caution.
Hydro Flask is a double-vacuum stainless steel bottle constructed to handle boiling water well, without damaging the bottle.
However, and this is very important, you must be aware that sudden temperature changes (like rinsing with cold water right after) can potentially affect the vacuum insulation over time. It’s something that is applicable to all insulated stainless steel bottles.
That’s the reason why I prefer disinfecting my Hydro Flask with white vinegar more than boiling water to minimize the risk.
Final Thoughts
By now, you’re all set with everything you need to know about cleaning your Hydro Flask.
The key is to make it a habit. Just a quick rinse every day and a deeper clean every so often to keep things fresh.
You’ve already invested in a quality bottle, so take care of it, and it’ll be with you for the long haul!
Jeremiah Kowalski
Hey there! I’m Jeremiah, the guy behind WaterBottleAdvisor.com. I used to have a bad habit of guzzling sodas while working remotely, but thanks to reusable water bottles, I’ve turned my hydration game around. After testing over 50 bottles, I’m here to help you find the perfect one to make staying hydrated a joy, not a chore. When I’m not reviewing bottles, you’ll likely find me scaling steep trails around the world, trusty water bottle in hand.
