Unless you like sucking through a stale, musty tube, it’s important to take the time to clean your water bottles, flasks, hydration bladders, and tubes.


It’s a pretty unglamorous job. But, once you see the inside of a bottle that hasn’t been cleaned (keep reading), it’s a job you’ll be more than happy to do… 

There’s also not much worse* than discovering your water bladder tube is full of mould the evening before setting off for a hike. (*discovering your water bladder has emptied itself in your pack the morning of is up there too. I can speak from experience). 

So, here’s how to clean all kinds of bottles, flasks and bladders. Not only will they be easier (and less flavoursome) to sip through, they’ll also last longer!


How To Clean a Water Bottle

Bottles are made of all kinds of things these days. Most commonly, stainless steel, aluminium, plastic, and glass (we wouldn’t recommend the last one for hiking).



Regardless of construction and the fact they may only contain water, not cleaning them is not an option.


How To Clean Water Bottles, Flasks and Hydration Bladders

Why you should most definitely clean your bottles… and not rely on the ‘eye test’.

Certainly, the most simple vessel to clean, follow these steps.

  • Thoroughly rinse
  • Clean with mild soap and water
  • Scrub the inside with a designated water bottle brush
  • Rinse again
  • Turn upside down and leave to dry (drying may be assisted with paper towel)

How To Clean a Hydration Flask

When we say flask, we’re talking about those typically associated with trail running — not inconspicuous drinking. 

These soft flasks are either tucked into pouches on running vests or into belt pockets for on-the-go hydration. 

Most soft flasks are made from TPU — thermoplastic polyurethane — which has properties in between plastic and rubber.



It means you may need to be more diligent with cleaning than a solid bottle to ensure longevity. They also seem a lot more fragile.

  • Disassemble and remove the cap
  • Fill with lukewarm water
  • Gently scrub the soft interior with a bottle brush (not the native tree variety)
  • Hang upside down to dry
  • Scrub cap and surrounds with warm soapy water
  • Ensure everything is dry before screwing back together (important)


How To Clean a Hydration Bladder

You can clean the body of the bladder exactly the same way as you would the hydration flask. Some bladders are reversible and can even go through the dishwasher, so check for the product recommendation. 

  • Fill with lukewarm water
  • Gently scrub the soft interior with a bottle brush
  • Hang upside down (or inside out if possible) to dry

The tricky part is cleaning the tube and bite valve itself — where the grime will most likely build up and where you put your mouth.

To clean;

  • Disconnect tube
  • Pull apart tube and bite valve (do-so gently and look-up your specific bladder model for instructions if needed)
  • Scrub both with warm soapy water
  • Scrub the inside of the tube with a dedicated tube brush
  • Rinse and dry before reconnecting


How To Clean Water Bottles, Flasks and Hydration Bladders

Quick Tips

  • Scrubbing makes all the difference as it removes any stuck on nasties

  • Bad smells and tastes happen if you leave bottles/bladders screwed tight with water still inside, meaning bacteria can grow. Drain and dry!

  • Some bottles/vessels are dishwashable, so check if yours is!

  • You can store empty bottles, flasks, and bladders in the freezer to prevent bacteria from growing


Other (literal) Cleaning Solutions

In addition, or as a substitute, to warm soapy water, you can also try;

  • Baking/Bi-Carb SodaA few heaped spoons dissolved into warm/hot water and soak for a few hours. Scrub afterwards. 
  • VinegarA few teaspoons of white vinegar mixed with hot water and soaked overnight. Don’t mix with the bi-card though, otherwise… boom! 
  • Anti-bacterial mouthwash
  • Cleaning Tablets – A dedicated bottle and bladder cleaning tablet like Bottle Bright is also a simple and efficient option.


How To Clean Water Bottles, Flasks and Hydration Bladders


Thirsty yet? 

Want to know more about bottles? Here are our answers to How Are Plastic Bottles Turned Into Outdoor Gear? and How To Purify Water in the Bush