Hiking Hydration

How much water and how to carry it?

Regardless of the gear we do or don’t carry and the passionate arguments about which is the best thingamajig, the one thing that you can guarantee is in every hiker’s pack is water.

Water is essential to our wellbeing and without it, we can’t survive. How long we can live without water is not a straightforward question and while the often-quoted figure is approximately three days, the answer is going to vary depending on many factors. Believe it or not, it is also possible to die from drinking too much water on a hike, it does happen!

As hikers, we should be carrying adequate water on every hike but how much water is enough? And how should we carry it?

How much water should I carry?

This question is a bit like asking ‘How long is a piece of string?’ In other words, a difficult question to answer that depends on many factors. However, it is a question you should be able to answer as you gain experience as a hiker. The factors that you need to consider include:

  • How long is the hike? Is this just a short half day hike or a longer multi day hike?
  • How far to the next guaranteed water source?
  • How hot is it?
  • How hard are you going to be exerting yourself?
  • How exposed to the elements are you?

Rough guide

Over the past few years I have been monitoring my water usage and now know that:

In the cooler months, I drink around 1 litre of water / 10 kilometres travelled.

In very hot weather (typically 30 degrees celsius +) I will allow 1 litre of water per hour.

Know what your water consumption requirements are likely to be based on the environmental conditions and your likely usage.

Fill up at every available water source.

Drink at the end of the day when you have finished hiking.

Monitor your water use and make sure you and your group members are drinking.

Use urine colour as a guide. This is not a perfect measure but if your urine colour is dark, then it is likely you need to drink more.

If you start to feel a headache coming on, it may be due to drinking too little.

 Now that you have some idea of how much water you need to carry, the next thing you need to consider is how you will carry the water.

Hiking time

Your first step should be to determine not just the overall mileage of your intended route, but the time you expect to take to complete it. Some shorter hikes may lack mileage but because of their steepness, the ruggedness of the terrain, and the elevation at which they take place, they may demand far more exertion and take more time than longer hikes on more moderate trails or at lower altitudes.

Water quantities

Once you’ve calculated the amount of time you expect to be on the trail, you should aim to carry enough water to allow yourself 250ml of water per half hour on the trail or one litre per two hours of hiking. This figure, however, represents merely a baseline allowance that may be affected by a number of variables.

Account for variables

The biggest variable in determining just how much water you’ll need to carry on any given hike is the temperature. While in cooler conditions the ballpark recommendation above of one litre per two hours of trail time will most likely be more than adequate, if out on a desert trail or hiking in midsummer, then you’ll probably need to supplement your baseline allowance with an added a half litre per hour of walking in order to replenish lost fluids.

Differing types of terrain take different tolls on the body. Both conditions underfoot and more general, large-scale variations such as rugged terrain, scrambling sections, and sustained ups and downs can all make for thirsty work…

The level of exertion likely on any given trail is usually easy to determine by measuring the overall ascent and the steepness of the trail, but a few other factors can also increase exertion levels and have us working up a thirst in a hurry. The most notable of these are a heavy pack and the altitude at which our hike takes place. If you’re carrying a ponderous load or tackling a trail above the 2,500m mark, therefore, be prepared to carry an extra few hundred ml of water per hour of hiking.

Personal metabolism and absorption rates

In every group of hiking friends there is usually at least one member who guzzles twice as much H20 as his/her companions and another who boasts the drinking habits of your average camel, seeming to be none the worse for taking just a few sips on even the most epic of hikes. The take-home? When calculating how much water to carry, take into account your own needs and adjust the amount of water you carry accordingly. If unsure, follow the guidelines listed above.

Know the Dangers of Dehydration

With so many other factors occupying our minds during a hike, it can be very easy to forget to hydrate adequately. Proper hydration, however, is crucial to maintaining our body’s ability to regulate heat, stave off thirst and cramps, and avoid the far worse symptoms of one of hiking’s most common and underestimated ailments—dehydration.

Symptoms of Dehydration

The most common signs and symptoms of dehydration include the following:


Headache, fatigue, weakness, irritability, light-headedness

Diminished urine output

Dark or pungent urine

Symptoms of shock


Treating Dehydration

Most cases of dehydration can be treated with rehydration salts, rest, and removal from exposure to the sun.

 If you suspect you or any member of your team is suffering from dehydration, take the following steps:

Stop hiking and sit the afflicted member down

Lie down in a cool, shady spot with your feet elevated

Take small sips of water mixed with rehydration salts or a salt and sugar solution

As with the vast majority of ailments out there, prevention is far easier than a cure.