To ensure you remain well hydrated and starve off the symptoms of altitude sickness you need to drink between 2-3 litres of water each day. We recommend drinking 500ml before starting your trek in the morning and then refilling before you set off.To carry 1.5-2 litres of water you will either have to take 2x water bottles or use a hydration bladder, which sits inside your daypack with a tube direct to your mouth.
It is common for water to freeze during summit night. To avoid having frozen water make sure that each bottle is well insulated. A good solution involves placing your water bottles inside a thermal sock, and then keeping the bottle inside your daypack (instead of exposed to the elements in the mesh pockets that sit on the outside of most daypacks). Another useful tip is to keep your water bottles upside down as liquid freezes from the top.
Water bottles/Platypus Hoser system We recommend you carry at least three litres of water per day. Make sure your bottles are thermally protected or they will freeze on the summit.Regular army-style water bottles are fine, though these days many trekkers prefer the new Platypus Hoser-style systems, or CamelBaks, a kind of soft, plastic bladder with a long tube from which you can drink as you walk along. They have a number of advantages over regular bottles in that they save you fiddling about with bottle tops and you can keep your hands in your pockets while you drink – great on the freezing night-time walk to the summit.But while they encourage you to drink regularly, which is good for dealing with the altitude, they also discourage you from taking a break, which is bad.
What’s more, these systems usually freeze up on the way to the summit, especially the hose and mouthpiece. One way to avoid this – or at least delay it – is to blow back into the tube after you have taken a drink to prevent water from collecting in the tube and freezing. (One reader suggested adding diarolyte which also helps to delay freezing.) So if you are going to bring one of these with you, make sure it’s fully insulated – and don’t forget to take frequent breaks!