How to Clean Your Hydration Bladder

When I posted my recent review of my new Osprey hydration pack, my hiker friend Wendy was excited. After our 10-day trek down the coast of Newfoundland on the East Coast Trail, her pack has stayed, well, packed. Her hydration bladder is now funky, stinky, and discolored, and she obviously doesn’t want to drink out of it. But that doesn’t mean you need a new bladder, woman! As long as there is no serious rip in the bladder or crack in the seal, the bladder is worth trying to save before spending mad money on a whole new hydration system. Before throwing away that bladder, try these steps:

  1. Fill bladder with warm water. If your bladder is covered in a film of black mold, add 2 teaspoons bleach, or a tablespoon if you have a very large bladder. For slightly less funky bladders, fill with 2 tablespoons of baking soda or a cup of white vinegar. Hold bag slightly above head, with hose down, and pinch the bite valve so the hose is filled with the bleach water. Let sit for a half hour.
  2. Drain water mixture. If you have the patience, drain it through the hose to make sure that hose and bite valve are both properly rinsed. Flush with clean water, then scrub with a gentle cleaner and a brush. Camelback and Osprey both sell cleaning packs, but you can use the same sort of brush you might already have in your kitchen for cleaning your water bottles and other hard-to-reach items. Flush again.
  3. If the bag still has a funky smell, residue, or both, soak again with white vinegar and let sit for another 20 minutes.
  4. If it STILL has a bad funk, fill it up again with 2/3 warm water and insert a denture cleaning tab. Let it sit for an hour or so, and then flush it out.
  5. This is the most important step. Most of the funk in hydration bladders comes from not properly drying out. When you are ready to call it quits, use hydration-pack-safe (contains no mold-loving sugar) electrolyte tablets to mask the taste of vinegar and mold, and promise to never, ever let your pack get moldy again, hand your bladder out to dry. Make sure the sides don’t stick together inside, or else it will get funky again. I prefer using a stand-up paper towel holder, but certain dish racks or even a cleverly-bent wire coat hanger will work. If you have none of those, stick a few paper towels in the top to absorb the moisture and give the sides some stiffness as the bag dries out.


In the future, if drying seems like too much of a hassle or if you live in a place (like Pittsburgh) where the concept of air-drying anything feels like some sort of incredulous myth, drain the water in your bladder and stick it in the freezer. This will save you the annoying drying stage while keeping the bladder inhospitable to harmful bacteria.


If your bladder is really funky enough to have to go through ALL of these steps and it just seems like too much work, or if you just want to treat yourself, then maybe it’s time for a bladder upgrade. If you aren’t buying a whole new hydration system, I recommend a Platypus bladder. It has a zip top, rather than a screw-on lock, and the hose is easily detachable. This means it is super easy to turn inside out to scrub and hang to dry between uses.