Gear Mod: In-Line Bladder Refill module

Well, the name is incredibly lame, but its actually a pretty good description of what the whole system does. This post is to show you how you too can modify your water bladder to allow for on the go re-filling, without having to take the bladder out of your pack. Its a pretty straight forward process, and Camelbak actually make the parts required, but its always nice to see how somebody else has done it, so you aren’t subject to their previous mistakes.

You will need:

  • A Water Bladder
  • A water-filter
  • Camelbak or similar 2 x male 1 x female hosing adapters
  • Pocket-kife / sharp blade]
  • Pliers
  • Appropriate sized PVC for your Filter out (5mm for me)
  • 8MM PVC piping for your water bladder in-line
  • Boiling water
Picture of required parts and tools

All parts laid out ready to start the modification

Once you have all the parts together, we can begin the process of modifying the tube. For me my tube length was actually about 15cm shorter than I really wanted; when it is in my pack, the tube only comes to my shoulder. This was a great time for me to make an extension to the tubing. Be aware, if you lengthen the tube, don’t extend it too much, otherwise sucking water though it will become increasingly difficult. Because I wanted to extend my tube, I measured out an additional 25cm of 8MM tubing to fix my mouthpiece and plug adapter to. (see above)

Camelbak adapter plugs

The Camelbak adapter plugs come with 2 males and 1 female

I made an incision just before the mouthpiece on the bladder hose, making a clean cut for the new female socket, and freeing my mouthpiece to go into my newly cut 25cm hose.  One socket comes with the 8mm terminating point and the other comes with a 5mm. For me this was absolutely perfect. I used the larger one for my bite module and the smaller one for the filter module. The female socket goes straight on the tube that runs into your bladder; allowing you to plug either the water filter in to your bladder and pump directly into it or put the bite valve on there for drinking out.

Filter tubing end picture

The Filter tubing module after the adapter has been connected

Mouthpiece with plug

The Mouthpiece tubing after fixing in the plug

Due to the shape of the socket and sizing of the hose going over it, the hose will probably require heating, I heavily recommend against using a lighter, matches or candle.It occurred to me after the fact, that PVC releases some pretty nasty chemicals when heated on a flame and that this could go through the pipe into the water. I recommend running boiling / very hot water through the pipe should you need to heat it up as this will still make the pipe malleable but is less likely to release those nasty chemicals.

Once you have heated the pipe its just a matter of using the pliers to pull the piping over the plug, this should be hard to do but that’s a good sign, it means its going to be hard to slide off as well. Hopefully you have a free bite valve as well, as you can see in the picture below that should simply push into the piping.

Base of Katadyn Combi

The bottom of a Katadyn Combi

Once those are complete, you should only have a loose run of 5mm tubing which you can run back to your water filter. I have a Katadyn Combi, which is technically only made to pump into water bottles, but using the 5mm hose, and a bit of hot water, I was able to make it pump through the hose.As you can see there is a small nipple piece on the bottom of the combi which is designed to fit into pretty much any water bottle. its also about 5mm in diameter which means a heated 5mm hose will fit over it very snugly. I believe that some of the other Katadyn and MSR water filters have 5mm outlets as well; with the rest utilising 8mm, either way it shouldn’t be too hard to make the hose fit. Once you have fit the 5mm hose over the end; you have something that looks like the picture below. To give you idea of the water flow, the water goes in the white tubing, through the water filter along the pipe and into your water bladder. Something that didn’t occur to me the first time, but was very visible after testing is; make sure that you prime the filter hose with water before you plug it into your bladder, otherwise, you will find yourself with the length of hosing worth of air inside your water bladder and no way for it to escape.

The Mouthpiece after the modification

The system after the modification


Camel back moudle pieces

Now our modular mouthpiece and water filter plugs can both go into the water bladder tubing

While this is a straight forward modification to your hosing, always measure twice and cut once. There is no going back once you cut the tubing!

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