I am upgrading my BOB and just bought a new pack with a hydration bladder. It will reside in the toolbox on the back of my truck.

Is it safe to leave water in the bladder or should I drain it after use? The water will freeze during a New England winter.

It depends on what type of bladder it is most likely. I have a CamelBak Thermobak and the documentation that came with it stated that the bladder could be partially filled and frozen.

However, I think the problem might be with repeated freeze and thaw cycles as might occur in a bladder stored outside in a New England Winter. If water should get into the non-flexible parts and then freeze I would worry that the resulting expansion could ruin the gear.

I'd just leave the bladder empty and store a container of water that might better hold up to repeated freeze and thaw cycles with your BOB. You could fill the bladder from the water container later, provided it wasn't frozen.

+! to izzy. Empty and air out.

-1 to izzy. (There are two heads to the coin)

When I return, I empty the bladder, refill half full, shake well, refull - absolutely full. If it has been over a month or so, I repeat before the next trip.

I never let any quality container freeze. I reuse the the high density PETE fruit juice containers for that.

Use a 1 or 2 liter soda bottle. They're tough enough to take the freeze / thaw cycle. And since it's in the toolbox, it's not getting the light needed to grow stuff. And they're basically free.

I guess I would wonder if a hydration bladder is truly an "upgrade" or not. As these posts demonstrate, bladders are complex and fiddly. I'll take any of several different varieties of plain old bottles, thank you. It's just water.

I have a 2 litter Camel Back in a small hydration pack, which is okay. I only use this pack in hot weather on short hikes, due to the small capacity of the pack itself.

When I recently upgraded my regular Day Pack to a Bergan's of Norway Pack which was hydration compatible.

After doing some research and talking to some people who used them I went with the 4 litter MSR Dromlite Bag for my day pack. You can get the hydration hose or the shower attachment for both the Dromlite and Dromedary bags. The threads are compatible with Nalgene wide mouth lids. I actually went with the shower attachment as I hike with my dogs and wanted a way to cool them off if needed.

http://cascadedesigns.com/msr/water-trea...te-bags/product

They also make this heavy duty version

http://cascadedesigns.com/msr/water-trea...ry-bags/product

and the hydration bladder version of the Dromlite.

http://cascadedesigns.com/msr/water-trea...-system/product