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Mountaineering Training | Hydration Stategies

Climbers heading to Rainier often ask the question, “water bottles or hydration system?” If you look around your local trail, chances are that most runners, hikers, and general recreationists are using a hydration system. Are these systems best suited to mountaineering, however?

In the past, many guides simply asked their climbers not to use hydration systems, but to carry water bottles instead. The belief was that the drawbacks of hydration systems outweighed the benefits. As hydration systems have improved to be less prone to leaking or punctures, this stance has shifted. There still are drawbacks to hydration systems, but given the right conditions, precautions, and expectations, they can be used effectively in mountaineering for a climb such as Rainier.

The main concerns we see with hydration systems are:

  • The hoses freeze: During midsummer climbs with high freezing levels, this doesn’t tend to be as much of a problem. On cooler climbs, however, ice buildup in the hose can quickly block any water from getting through. The neoprene hose insulators are not particularly effective, and it doesn’t take much ice buildup to completely block the flow. Blowing the water back through the hose after every drink can help, but still isn’t 100% effective. The best practice is to bring an empty, water bottle (even if only ½ liter capacity) that you can pour the hydration bladder into should it freeze so that you still have access to water.
  • Rationing water: Climbers can only carry so much water for a climb before the weight becomes cumbersome. Typically we recommend 2-3 liters of water for a Rainier summit day. This is plenty, but requires climbers to ration it; for example, 2 liters allows a climber 1/3 of a liter of water at each break. If climbers are sipping more consistently from a hydration system, often they lose track of that rationing, and find themselves partway into a climb, with no water left. Diligent attention is the only way to solve this, and this is difficult when you can’t actually see how much water you have left.
  • Distractions: Trying to turn a hydration hose on and off and drink from it on the fly distracts from the climbing, the terrain, and the overall situation. When climbers are roped up and climbing, each member of the team is relying on all of the others to remain vigilant to catch a fall and to not cause a fall. A hydration hose is a distraction from this, and the solution is to either keep the hose tucked away inside the pack (where it is inaccessible) in climbing terrain, or for climbers to carefully assess the hazards of the terrain they are in at that moment, and to choose benign stretches to get their hydration.


Hard, plastic water bottles have been the standard in mountaineering for decades and still provide the simplest method of carrying water. They generally do not freeze, it’s easy to see how much you are drinking, and they are away in the pack while climbing. That being said, since they are tucked away in the pack, they are inaccessible and do not allow a climber the opportunity to get a quick sip of water on a long stretch. Hydration systems may have a place in your mountaineering kit, but practice with them, have a plan and know how to minimize the drawbacks. If in doubt, water bottles will still work fine!


Questions? Comments? Share your thoughts here on the RMI Blog!

Comments (4)

Please tell me what type of bottle for mountaineers is used what you should think about a water bottle which have everything you need what type of water bottle is good what thing you think will there in water bottle. I am designing a water bottle

Posted by: Tanisha on

I use a bladder in winter here in the north east and have done so for years. Just have to be mindful to mitigate freezing.

I spend up to multiple weeks solo on snowshoes and it gets pretty cold out here.

We had a week straight where temps hovered in the mid -20s °F last season.

I was on trail and had no problems.

My hydrations sleeve is lined with reflection film(did that myself) and I fill the bladder with warm water on cold slogs.

This is not the pack sleeve that is lined but the separate sleeve that came with my Camelbak.

As long as you blow the line out it works fine.

My sleeve that runs on the feed line is modified as well.

A bit is also dependent upon how the bite valve is set up.

Also, the being able to see what is in your nalgene is out of the proverbial window to a large degree if you utilize and insulated sleeve on your 1L(ie OR/Nalgene.)

Granted you can look down into the bottle but its still a crap shoot unless you take the bottle out of the sleeve and look or try to line the water lever with your finger on the outside of the bottle.

I can see the whole distraction thing while on the move but if your stagnant in a congo line you cant take a sip out of a bottle without dropping your pack to get to the bottle being you dont know how long you will be static.

With a hydration system this is a non factor.

There are pros and cons to both approaches as with anything.

Posted by: Loco Raindrops on


For the sections of glacial climbing that we do on Rainier, we ask climbers to have all water bottles inside their pack, as anything that finds a way to escape the pack potentially becomes a projectile (not unlike a rock) that can injure climbers below us. Great thought though.

—The RMI Team

Posted by: The RMI Team on

How about clipping a half liter bottle to a pack strap with a minibiner?  That way it’s attached to you and easily available when needed.  Maybe not best for when doing technical sections but for ordinary glacier travel not bad at all.

Posted by: Boris on

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