Stupid Internet Bushcraft Stuff #3 Attempting to build a tolerance to contaminated water

Over the years, I have heard some pretty dodgy advice from people who do not know what they are talking about but this one was repeated to me recently.

In countries or places where the water is not safe to drink, just mix a little bit of dirty water into your clean water, about 10% dirty to clean they say.

This is bad advice.

The most recent person who suggested this claimed to have never had a problem and soon worked up to drinking only dirty water with no ill effects whatsoever.

The key piece of information that these people are missing is that bacteria and protzoa, the causes of most water borne problems are microscopic and the mechanism in which they ¨infect¨ and the severity of the symptoms that they cause are not equal to the amount of them that you ingest.

A Giardia worm does not care if it is alone of if it surrounded by many hundreds of thousands of it´s friends however there is some evidence that suggests that the amount of some parasites in your body are directly proportional to the severity of the symptoms that you receive.

There are few reasons to drink dirty water, building a tolerance to it is not a biologically sound idea though as for this to work, even hypothetically, you will have to first become infected in order for you body to learn how to produce antibodies to the infection in the first place.

This has come up on courses and expeditions that I have run and my advice is always the same.  Do not take chances and serious risks with your health through ignorance.  Being in blissful ignorance has got most of us through some tight squeezes in life but we, as a civilisation, know enough about how waterborne infections occur that we do not need to take such risks.

A sick person is a liability to a group.  In a wilderness expedition, a person who has become sick through an entirely avoidable circumstance put´s other people at risk and can ruin a whole expedition.

There is no tangible benefit to be gained without you paying the price of infection.

Water, water, everywhere. But not a drop to drink

The average human body contains 40 Litres of water, which is roughly 57% of our total body weight. We need water more than anything else with the exception of oxygen. Water is critical to our continued survival. We need water to carry nutrients around the body to aid digestion of food, to regulate body temperature and remove waste and toxins from the body.

We obviously also use it to wash and maintain hygiene.

The average person in average conditions can survive no longer than 3 days without water.

On average, under normal conditions we need about 2.5 litres of water per day, of which we get about 1 litre from the food that we eat, about 300ml from chemical reactions at a celular level and the rest should come from drinking.


Dehydration is defined as the excessive loss of water and electrolytes. If we dont drink enough we become dehydrated.

Symptoms include

  • Decreased urinating
  • Dark and foul smelling urine
  • Dry and sore lips
  • Thirst
  • Headache – a dull, thumping headache much like a severe hangover
  • Tiredness and Fatigue
  • Seeing stars when standin up suddenly
  • Dizzyness and Fainting

More serious symptoms include

  • Delirium
  • Seizures
  • Sunken eyes
  • Increased respiration and heart rate
  • Death

The only effective way to treat dehydration is to rehydrate. In severe cases the victim should be encouraged to sip water little and often to gradually bring ther hydration levels back to normal levels. If they gulp it down, and they probably will want to, it may induce vomiting which compounds the problem and causes further loss of water.

An electrolyte drink should be carried in your equipment, these contains salts and minerals that are lost during sweating, diarea. There are many electrolyte drinks on the market but if you dont have one, they can be improvised by adding one tea spoon of salt and one tea spoon of sugar to one litre of water.

In practise, when out in the wilderness, hiking, camping or in a real life survival situation our diet’s are not full of fruit and veg, we are unlikely to be getting our 5 a day and a lot of purpose designed expedition food is dehydrated in the first place. Combine this with hard, sweaty work and the outcome is that we need to drink a lot more.

In hot conditions, deserts, jungles and even the UK during summer months, excessive sweating, which is our body’s way of keeping us cool, cause us to loose water at a higher rate that is considered normal. It has been known for people in the desert to drink up to 9 litres of water a day while they are becoming accustomed to the heat.  Once the body acclimates, the amount of water that they require have to drink reduces to a more reasonable amount.

Pay regular attention to the colour of your urine, clear or straw coloured is a good sign. Brown, yellow and smelly is a sign that you need to drink more. Thirst is not a reliable indicator as by the time you feel thirsty, you are already dehydrated. Our aim is to stay hydrated and at peak performance.

How do we know that water is safe to drink?

We dont, there is no way to tell if water is safe to drink by looking at it or smelling it. There are indicators such as dead animals, dead vegetation or animal remains that could indicate a problem with the water source but the absence of these indicators does not confirm that the water is safe.

If we see birds or animals drinking from our prospective water source does this mean that is is safe for us to drink? No, most other animals have more tolerant digestive systems to our own. Think about your dog at home who eats just about anything he fancies, including other dogs feces with no ill effects.

Does that mean that dog feces is OK for us to eat? No, it means that your dog has a tougher digestive system than our own.

The problem is that many of the contaminants that can hurt us are microscopic.

We must treat all water sources with suspicion in order to avoid a number of unpleasant and sometimes life threatening problems.

Lot’s of people that I have taught assume that running water, that is a fast flowing stream or river will be safe to drink. I’m afraid that this is not the case, it is however advisable to collect water from a running source it will generally be less turbid and clear

There are five categories of Contaminants that we deal with before drinking water collected from an unknown source

Turbidity – Cloudy water containing mud, plant matter animal feces and other organic matter. Turbid water can cause upset tummy’s and can fortunately be filtered by using a tightly woven cloth such as a couple of socks put one in side of the other or a purpose designed filter such as the Milbank Bag.

Milbank Bag

Parasitic Worms – There are many different worms that live in water, notably amoebae which causes dysentery and Giardia lambli which is a particularly unpleasant worm to catch.

These can be killed by boiling the water. Bringing the water to a rolling boil, until it bubbles up is sufficient to kill the worms.

Chemical treatment is also known to be effective providing that you follow the instructions fully and give it enough time to work. However, Cryptosporidium is know to be resistant to Chlorine and Iodine so where possible it is best to boil the water.

BacteriaAgain, Boiling is effective against all bacteria and there are some nasty ones in there that we really don’t want inside of us, E-coli for one. Boiling and Chemicals will kill them.

Viruses – Things like Hepatitis A and E and even Polio can be present in water, again, Boiling will kill these.

Chemicals – Pesticides and agricultural run off along with heavy metals fall into this category. They can be a pain to remove but can be by means of a carbon filter. Area’s to be wary of are agricultural area’s where chemicals are used in the fields (most of the UK low land area’s) and mining area’s for heavy metals. The risks form Chemicals are far outweighed by the Parasitic worm, Bacteria and Virus risks.

Metals – Things like Mercury and Lead are toxic.

Filter and boil all of your collected water and you should be fine.

Collected fresh rain water does not need to be purified.

I mentioned Chemical treatment several times up above, Chlorine or better still Chlorine Dioxide which works faster are what I was referring to, both are readily available fro outdoor / camping supply shops. Iodine is no longer on sale for water purification purposes in the UK which is not to say that it is not an effective disinfectant, it is, but for political reasons it has vanished from the shelves.

Sawyer Mini-filter

This thing is a bit of a revolution in mobile water purification, it is tiny and has a universal screw thread so that you can attach it to a wide range of different water containers and if maintained correctly by back flushing to clean the filter, it will be good for about 100,000 Gallons (US) which is a lot.

I have faith in this product not only because I have used it all of the world with no ill effects but because they test the water that they purify and publish the detailed, unedited results of those tests.

They test water from a range of different sources and even some with known contaminants.

An example can be found here

Finding Water

So now that we know what to do to make our water safe to drink, where do we find it?

There several indicators that can give you clues to the whereabouts of water.

First of all, water runs downhill, so looking around at the foot of hill and mountains will invariably yield results. Plants and trees can also betray the presence of water, Willow tree’s for example prefer wet or damp ground as do Reeds, Cat tails and some Alders.

Several species of bird live on, in or around the water such as Heron, Ducks, Swans, Geese and Finches. Observe their movements and follow them and you may well be led to a water source.

Indian Well – If you dig a hole in the ground, as long as you go deep enough, you will eventually hit what Is known s the water table. In many areas you may not need to dig very deep, In some areas you may need to dig deeper than is reasonably practicable.

If your going to dig, remember that water runs downhill and look for low ground or natural dips in the terrain. When you hit the water table, allow it to fill, scope out the muddy water and then let it fill again, this time the water will be clearer.

Rain water will also collect in the base of tree’s. Older and coppiced tree’s often have natural bowl shapes in them, Oaks especially, these can be useful reservoirs on the trail.

In extreme cases you can retrieve water from vegetation by tying off a plastic bag around a branch with lots of leaves on it. Allow condensation to collect on the bag throughout the day and return later to collect your drink. This is not an especially effective way of sustaining yourself but with enough plastic bags you could set up large scale water harvesting system.

Dew. Collecting morning dew that has collected on grass and other vegetation is an easy way to get a drink, simply tie off some spare clothing around each leg and as you walk through the vegetation the dew will soak the clothing tied around your legs. This can be wrung out into a cup and drunk.

Again, this is not a high yielding method of water collection.

Salt water distillation. At sea or in coastal area’s you may find yourself remembering the words ‘water water everywhere but not a drop to drink’. You cannot drink salt water, it will kill you faster than dehydration. You can remove most of the salt by heating up the salt water and collecting the steam which is fresh water. However, in coastal areas there will be many fresh water outlets finding they´re way out to sea where all rivers flow.

These coastal outlets where fresh ground water is finding it’s way out to sea can be a life saver, they are not always large flowing river, sometimes they are merely drips, of trickles of water seeping out of a crack in a rock like a dripping tap. Put a container unde it to catch it and move on to soemthing else, come back in half an hour and you will surprised to find that the water has collected and that you have a near infinte supply as long a you are prepared to wait for it.

Stuffing a rag or a bit of cord into a damp crack in the rock face can help you to wick the water into your bottle.

Getting Water in a Frozen Land

When everything is covered in snow and otherwise frozen, finding water to drink can be harder than you might think.

I am staying in a pretty remote log cabin which is nice but it has one drawback, there is no obvious water source.  I like to be self reliant and independent so this is an obvious problem for me.

You may think – Well I will just melt some snow and it is true that snow is basically just frozen water and air.  The trouble is that it is it seems that snow is mostly air, not water.  The colder it is, the more air the snow will have in it.

At the moment, while writing this, it is a balmy -10 c which really is not that cold so the snow should be less airy than it usually is.

I have filled a 2 liter pot with snow and compacted it down as much as possible to get as much snow in there as I can.  I intend to melt this down and see how much water it gives me at the end.

It is worth noting that snow takes a long time to melt like this.  This 2 liter pot took 20 minutes sat on top of a very hot wood stove.

While we wait for it to melt I will remind you, the reader, that we need to drink quite a lot of water in a day.  Up here in the arctic, I am drinking about 3 liters a day and am still feeling slightly dehydrated at times.  This is because my body is using my own water to humidify the frozen air as I breath it.

Melted snow water is still liable to contain turbidity, debris and the other range of contaminants such as protozoa and bacteria so must be regarded with suspicion and treated accordingly.

Ok so that took 20 minutes to melt, indoors, on a hot wood stove.  My 2 liter pot yielded about 500ml of water.  So just to get by with drinking water, not accounting for cooking or washing, I would need to collect 12 liters of snow per day and spend at least 2 hours melting it.

As you can now see, snow does not represent a convenient water source in the cold north but if this is all that you have then this is what you will have to accept and deal with.

Ice on the other hand, has far less air in it and is mostly water. if you find any ice then go for that first, once melted, it will yield far more water.