Water Purification/Cleaning

Water is a necessity for us to function properly. When the fluid level becomes lower in the body, both physical and mental performance deteriorate. But how much water do you need to drink? What water is okay to drink? And what’s the bets way to purify the water? This will be the subject in this guide.

You have no idea how many times we have had to help hikers we met in the forests who carry too little water with them and completely lack the knowledge on how to get more! But this is also something that even more experienced hikers can have problems with. What you then end up facing is a situation where you quickly get tired, lose your temper, and with that run a much greater risk of getting hurt. Already after a couple of days, you will be significantly affected by the lack of fluid intake.

How Much Water And How Should You Drink?

First, we would like to say that there’s a difference between individuals in how much fluid one needs to stay on top. But start with what you drink during a normal day as a minimum before your trip. Then try to add the fluid that the increased activity level and any heat may bring. Hikers here in Sweden usually refer to our military’s survival handbook, which says that an adult needs roughly 2.5 liters/84.5 ounces of water per day. But even this figure is with a lower level of activity. So on a really demanding hike in warm temperatures, you can often end up needing on up to 4-5 liters / 135-170 ounces  of water.

When it comes to how often you should drink, it is usually said that you should try to drink smaller amounts but at frequent intervals. One method of achieving this is by have the water more easily accessible. We, therefore, recommend using a hydration bladder or a bottle with a connected tube. You can then easily take a sip every now and then while you walk. But lets say you drink a large amount of water at once, it will probably result with the need to pee sooner than you think. But don’t get us wrong. It is not wrong to properly fill your body with water. But when the water needs to last a longer distance, it can be counterproductive. And too much water in a short period of time can lead to dizziness.

Drinkable water pouring down from mountains in northern Sweden
Fridh, Andreas.

Drinking Unfiltered or Unsterilized Water

A number of consequences can arise from drinking unfit water. Among the most common are stomach ailments. Something that can be tough enough for the body in a comfortable home environment. But when you lie in your tent without a toilet, shower or even clean tap water, the situation can quickly get out of your control. You can then be forced to cancel, or in the worst case, call for help if you get too sick.

There are lots of other unhealthy things that can enter you body trough unfiltered and unsterilized water. Such as the parasitic disease Giardia, also called Beaver Fever. Its symptoms only appear after about 1-2 weeks in the form of explosive diarrhea and foul-smelling gases and in some cases need to be treated with antibiotics. This is obviously something you really want to avoid!

4 Ways To Make Water Drinkable

Okay, there are probably more than four ways to purify water while hiking. There are for instance several different solutions you buy but also many improvised filters you can make on your own. But in order to be sure that the water is purified, we choose to present four methods that are guaranteed to work. Which of these you choose depends on what your individual needs and which impurities you might encounter. But regardless of which method you choose, the following applies: Always read what your preferred cleaning method can handle!

Purifying water using the filter Sawyer Mini
Fridh, Andreas.

1. Clean Water Using Filter

Water filters are probably the most versatile cleaning system you can choose. Assuming you buy the right filter, that is. For some models, simple bottles are filled with water which then a filtered while you drink, while other has some form of pump. But the most versatile are those that you can mount inline, mount straws on, or screw onto a bottle. A major manufacturer of this type of filter is Sawyer. These can also be used as gravity filters in you have a hydration bladder! Some filters can be backwashed and thus extend their life, while others clog relatively quickly. So read carefully before buying.

Pros Cons
  • Removes particles
  • Versatility
  • Quick water purification and "on the go"
  • Models to remove heavy metals and chemicals
  • Some models require maintenance
  • Sometimes expensive
Boil water to clean it and make in drinkable
Fridh, Andreas.

2. Purify Water Trough Boiling

This is a classic method that has been used for countless years. It requires no additional equipment beyond your outdoor stove and cookware and can also be seen as the cheapest method. It works in such a way that when you boil the water, any bacteria and viruses die. But how long does the water have to boil? The Swedish military’s survival manual recommends a ridiculously long cooking time of a full 20 minutes. But the fact is that most bacteria die already when the water starts to boil. But to be on the safe side, we usually recommend 2-3 minutes. The rule of thumb is: Big bubbles, no troubles.

Pros Cons
  • It heats up the water for cooking
  • The possibility to melt snow and ice
  • No additional equipment
  • Takes a long time
  • Consumes fuel
  • Doesn't remove particles
Water purification tablets can purify water for you on your hike
Fridh, William.

3. Water Purification Tablets/Drops

This method is usually based on chlorine or iodine that dissolves in the water. You add them and wait 10-30 minutes for the substances to purify the water. Chemical cleaning usually takes up little space and has a low weight and is thus a good backup for, for example, a filter. The downside of chemical cleaning is the time it takes and the potentially unpleasant taste in the water.

Pros Cons
  • Required little space
  • Easy to portion out
  • Effective
  • Slow purification
  • Some chemicals has limited effect on some viruses and protozoa
  • Expensive
  • Doesn't remove particles
Steripen Ultra can clean your water and make in drinklable
”Steripen Ultra”, Katadyn, katadyn.com, 30.11.2019

4. Purify Water Using Ultraviolet UV Light

The most advanced option on the list is undoubtedly UV light. The light destroys the organisms’ ability to reproduce and they thus become harmless. You put the transparent end of the lamp into the water and wait for a specified time, usually around 90 seconds. The lamp has a long life, is surprisingly fast and usually has very good cleaning properties. The disadvantage is that they run on electricity, but with a power bank you can clean a large amount.

Pros Cons
  • Compact solution
  • Affective against a wide range of microorganisms
  • Fast
  • Flexible
  • Required electricity
  • Somewhat fragile


With this text in mind, we hope that you make a good choice when it comes to choosing water purification method. And that you above all avoid water that might not even be worth trying to clean! Also, remember to drink small amounts but often to avoid dehydration during your hike.


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