How To Clean A Hydration Bladder The Easy Way

Hydration bladders can be an essential part of staying hydrated while adventuring. But even if we only fill these water reservoirs with clean, filtered water, mold and bacteria can grow and quickly become a health hazard. That’s why it’s critical to clean them every so often. So in this article, I share a guide on how to clean a hydration bladder, tips on how to keep it cleaner for longer, and answers to frequently asked questions.

Tips on using water bladders and optimizing cleanliness

Following a few simple best-practice tips when using a hydration bladder can make all the difference in keeping your water reservoir cleaner for longer.

• Only ever use reservoirs and bladders for water. Any other liquids will increase dirt and residues.

• If you use bladders for electrolytes or anything sweet, the inside of the reservoir, tube, and bite valve will become sticky with some dirt buildup, and cleaning will be more difficult. Sure, you could buy replacement tubes and bite valves, but that’s a little wasteful and will get expensive quickly.

• If you’re sourcing water in the wilderness, only put clean, filtered water in the reservoir. I’d suggest using another pouch for the raw water, which you then filter into the bladder. I use a Sawyer water filter for this and it comes with a reusable pouch.

• You can also extend cleanliness between deep cleanses by draining and drying the bladder out or freezing it.
  • When almost empty, I typically drain the remaining water and hang it upside down to dry.
  •  If there’s plenty of water left in it, I put it in the freezer to freeze to avoid wasting water. Just remember not to freeze it if the bladder is full. Drain a little bit out to allow for the expansion of water into ice. You don’t want to end up with a burst bladder or even a slow-leaking one for your next trip. Freezing a water reservoir is also an excellent way to get rid of nasty taste issues.

5 steps to deeply clean a water bladder

You could simply use dishwashing soap and hot water to clean a hydration bladder. Give it a good shake and use a sponge or brush. However, I also find it more efficient to use effervescent tablets and a reservoir cleaning kit, because they come with super useful accessories.

If you’re looking for an all-in-one kit to get started with reservoir cleaning, I would highly recommend this water reservoir cleaning kit! It comes with cleaning accessories such as brushes, a hanger, cleaning tablets, and a carrying pouch. It’s the best value for money that I could find, has thousands of 5-star reviews, and is what I would buy right now if I needed one.

Step 1: Empty your water reservoir

Get that old or “half-used” water out to prepare for the soak. If you have plants around the house or garden, now is a great time to water them!

Step 2: Clean the hydration bladder, tubes, and valve with brushes

Using dishwashing liquid, I use the brushes from the reservoir cleaning kit to scrub the inside of the reservoir and the tubes. At this time, I disconnected the bite valve, straw tubes, and reservoir.

I drop the bite valve in a glass of hot water and squeeze it again to try and get any last pieces of dirt in there. Then I use the thinnest brush to pass it through the drinking tubes after dropping a little dishwashing soap on the end of the brush.

And I use the larger brush to scrub the inside of the reservoir, again with some dishwashing soap. Pay close attention to the corners and edges of the reservoir, where dirt and mold are most likely to build up.

If you only have dishwashing soap, skip to step 4! Otherwise, onto step 3!

Step 3: Fill out the bladder again and let it soak with a cleaning tab

If you have cleaning tabs, connect all parts of the bladder system together again to deep clean the bladder and remove any nasty taste residue.

I find these cleaning tabs to be the best way to neutralize odors and they will also get rid of mold if it’s starting to develop. Not only can they clean water reservoirs, but they can also clean your water bottles, flasks, and other kitchen items.

To soak my reservoir, I keep the tube and bite valve attached. I fill the bladder with hot tap water and drop fizzy cleaning tablets in the water (1 tablet per liter). I wait for the tablets to dissolve before shaking the reservoir a little.

Next, open up the bite valve and squeeze it with your fingers to get some cleaning water through the tube, to ensure it gets a good clean too. Close the valve again so the water sits in the tube.

Then let the soaking begin! Typically you can let it soak for 15-30 minutes. If your bladder is very dirty, you can leave it to soak overnight.

I usually let mine soak overnight every time, unless I’m really short on time, to ensure a thorough clean.

Step 4: Rinse the reservoir, tubes, and valve

After the time has elapsed, drain the water again. Here I drain some of the water through the tubes by squeezing the mouthpiece (after opening the valve) so that it gets a little cleaner too. For this to work, raise the bladder a little higher than the tubes, so that gravity does its job.

Rinse the reservoir, tubes, and bite valve thoroughly with clean water to remove any remaining soapy residue.

Step 5: Dry the bladder, tubes, and valve

I find the best way to dry my hydration bladder is to use the hanger from my reservoir cleaning kit. As shown in the picture below, I hang the reservoir upside down on the hanger. And I hook the hanger above the sink on my top kitchen cabinet doors. I love this because I can hang both my water bladders and their tubes. Another thing I do here is slip the slide-seal through the opening of the bladder, to force airflow, so that the inside can drain and dry more quickly. You could also use a regular clothes hanger and obtain the same results.

The most important thing to do is to let it dry completely before using the bladder again. You could use a dry towel to speed up the process, but bacteria will grow again if it does not dry out in full at this stage.

About the hydration bladders featured in this blog posts

The bladders featured in this post are the Osprey 2.5L and the Osprey 3L reservoirs. I have used them for several years, without any issues.

When I was first looking for a water bladder, an REI rep advised me that it is best to take a top-fill one rather than a cap-fill one, because top-fill systems are less prone to leaks. I’ll be honest, I have never owned a cap-filled one, so I can only go based on my top-fill experience. All I know is that I have never leaked, I love both these top-fill water reservoirs so much. They are part of my lifeline when I’m out adventuring.

Also featured in this post is the Osprey reservoir cleaning kit. I am really happy with that purchase and would recommend it to anyone interested in purchasing a cleaning kit.

Frequently asked questions about cleaning hydration bladders and water reservoirs

Should I clean my water bladder before first use when it’s brand new?

Yes, it is a good idea to rinse your brand-new bladder. A little soapy water before first use will be enough to ensure any manufacturing residues wash off. Just don’t forget to let it dry completely before using it!

How long can you leave water in a hydration bladder?

How long you can leave water in a hydration bladder depends on usage frequency. If you use it to go hiking every day or every weekend, you can get away with keeping the water in there. Perhaps keep it in the fridge or freezer in between trips. If you only use it once a month, it’ll be better to drain and dry the bladder until your next outing.

How often should you clean a water bladder?

Cleaning frequency depends on usage frequency as well. You could get away with cleaning it every few months if you use your hydration bladder lightly. But if you’re using it a lot, like for an extended backpacking trip, it’s safer to clean it when you get back, even if you only just washed it before your trip. If you don’t clean it for a while, you’ll notice the bladder starts to turn a little yellow, or at least mine does. So I’m sure you will know when to clean yours.

Post originally published on May 25, 2023, and last updated on May 9, 2024.