Safe and effective ways to purify drinking water when hiking

It was a perfect blue sky with an eager sun reflecting off of the hard granite stone of the Glyders.

Andy and Paul on Tryfan


I was with a small group of friends (none of us really mountaineering experts) that had climbed Tryfan, we had just finished both of the Glyders. In our minds it was a perfect day not a cloud to be seen, the views were spectacular, but boy was it hot. There was not the faintest hint of a breeze on the top of the mountains, the sun seemed determined to drain every last ounce of energy from us intensified by the unrelenting sheen from the hard faced rocks.

Don’t get me wrong it was a fantastic day, we could not have asked for better (ok a breeze would have been welcome,) we were loving it. We had stocked up on water bottles for the walk but by the time we were coming down Glyder Fawr there was not a drop to be found in any of them and we were gagging!

The relief in finding an ice-cold spring coming out of the mountains near the Devil’s Kitchen cannot be described, we drank it, filled our bottles with it and splashed our hands, faces and necks in it.

Drinking from spring on the Glyders


It is not very often in this country that you will find yourself in a place where there is not reasonable access to clean drinking water in the vicinity. Occasionally like us, a situation occurs where you run out of drinking water and dehydration is a potentially serious problem.

Some may chose, or like us find themselves in a situation where, using drinking water from a natural source is the only option. We were fortunate in finding a spring that ran clear and was fit to drink, generally speaking I would not advice anybody to drink from a natural water source, no matter how clear a stream may look or how high it is up the mountain.

When walking a long distance path or when wild camping, carrying a great quantity of water for miles is not an appealing idea. Being able to drink from a natural water supply that is easily to hand is a much more satisfactory. There are several ways to purify water in the wild, here are three of the easiest and most effective.

Methods of water purification

Boiling water

Vango cooking system

Boiling water is an effective method of purifying water. Waterborne Pathogens are killed within one minute at temperatures above 70°C . It follows then that if you boil water by the time it has reached boiling point the pathogens (they are the things that give you a bad stomach, or worse) are dead. If you want to make extra sure that they are exterminated then boiling water for only one minute will do.

Some people say that the water should be boiled for longer (5 to 10 minutes) but this is not true.

Boiling water is fine if there is plenty of time, at the camp site for instance, but when on a walk I find it a pretty time-consuming process. That is ok if I want to take my time, but often on walks I am pretty keen to press on. It takes time to get my cooking kit out of the bag and set up; then, not only has the water got to boil but afterwards it needs to cool down before pouring it into a water bottle.

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Water purifying tablets

Chlorine or Iodine tablets are very effective ways to kill all pathogens. they are simple and easy to use. Just drop a tablet into the container full of water and wait for the chemicals to work. It has been a long time since I used Chlorine tablets, the only real disadvantage I found with them was that the water was not instantly available to drink.

A pack of tablets is very small and light, the water does require filtering with a cloth or something similar to remove any organic material and there was a bit of a chemical after taste.

Tablets are my least prefered method of purifying water, I would only use them if I had to.

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Filtration methods

The most popular system of water filtration is the Sawyer water filter. This is a lightweight hand size tube containing a filter that captures 99.9% of all harmful protozoa and bacteria. It is very popular with walkers on long distance through hikes across the world.

The Sawyer filter is pretty quick and easy to use, either to filter water into a drinking container, or the Sawyer filter can be connect to a drinking tube which is connected directly to untreated water. I like the fact that the filter can be used to provide drinkable water instantly, I do not want to have to wait for water to purify when I am absolutely gagging for a drink, even filtering water into a container is pretty quick and easy.

Even though the Sawyer filter can be used in water in almost any state, it is best to try to avoid as much as possible too much organic matter, which could block the filter.

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Water to Go

Clive drinking from a Water to Go Bottle


This is a drinking bottle with a difference, it contains its own water filter. It weighs slightly more than most water bottles, but I think that this is more than compensated for by the fact that water can be sourced for the bottle from anywhere so long as it is not saline. This means that I only need to carry as much water as the bottle holds, when it is empty I just simply find any water and refill. Water is instantly available to drink

The Water to Go bottle filters out 99.9% of all bacteria, protozoa, chlorides and harmful metals, so it can also be used if you are a bit wary of tap water. Try not to get too much organic material in the water, it just clogs the filter up faster. The Water to Go bottle will filter 200L of water before it needs replacing.

It is the simplest and quickest water purifying system of the four mentioned here, simply grab the bottle from the side of your pack!

What I also love about this bottle is that it helps cut down on the use of disposable plastic bottles.

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Content Writer

I have loved walking in the in the great outdoors as long as I can remember, weather is not an issue and any landscape is a new adventure. Personal details:- Height 5'10"(1.78m), Wt 12st10oz(81kg) Chest 41"(104cm) Trouser size 32"W,32"L, Baselayer/midlayer size medium. Hardshell layer size large.