Wild Camping Part 4 – Water Purification

We went over water carriage last week.  But how can we get it into our drinking vessels in a safe form.  The answer most people instantly give is ‘use a water purification system’.  This isn’t wrong but these can be bulky, heavy, expensive and sometimes unnecessary.  So let’s look at the steps to take before this is required.

Water purification devices are vast in their number, different uses and benefits and the correct selection depends on what dirt, bacteria, viruses and nasties you want them to rid you of, how much they’ll filter per minute and how portable they are.  It takes a bit of research to get the right one for your specific needs and there are always improved versions being brought out.  I’ll do a review of the commercially available ones in the future but today will deal with the simple and DIY methods to make your water supply safe.


Let’s start at the beginning, the simplest level – site selection.  This is easy as it requires no tools or techniques just sensible selection of where you collect your water.  The closer you can get to the source the less chance it’s had to become contaminated.  So a spring is better than a stream and a stream is usually better than a river. But location is also a factor.  A river in the middle of the Scottish Highlands is likely to be more pure than a stream running through an urban area. It’s all about thinking about the potential for contamination.  Sources of pollutant needn’t only be domestic or industrial. A stream running through agricultural land could have pesticides or animal excrement in it…or worse. There is an old Scottish saying that ‘you shouldn’t drink from a burn (a stream) as there’s always a dead sheep upstream’ – ‘always’ is a bit of an exaggeration but the sentiment is true – the closer you get to the source the more certain you can be that nothing dodgy has entered the water.


One of the first cleaning methods to consider is boiling.  Everyone knows how to boil water.  How long to boil it for actually depends on your altitude since water will boil at a lower temperature higher up and therefore  you need to boil it for longer to kill as many beasties. However, for this simple introduction we’ll keep it to more sober altitudes and I’d advise bring it to the boil then keeping it on a rolling boil for a good 5 minutes to be sure.  That’s 5 minutes from when it starts to boil. This may be more than required but I’d rather wait an extra few minutes than dealing with the consequences of drinking water akin to pre-flush toilet water.


Boiling can kill the bugs that live in water but it won’t remove particulate, a fancy way of saying dirt, grit and floating bits.  So before you boil the water you may want to filter it.  This is simply a matter of creating a sieve. I’ve strained water through a sock, sand, charcoal, some sphagnum moss or tightly packed dried grass.  These latter two need to be clean…otherwise you’re defeating the purpose. Creating a filter with differing layers that have increased filtration is great. So a funnel (e.g. a plastic bottle with the bottom cut off or the sleeve of a waterproof jacket) with gravel at the top, followed bygrass, moss, then sand and finally ground charcoal would be great.


You can use UV light from the sun to kill bugs in the water but for this you’ll need clear containers and plenty of sun.  The containers can’t be too large and they need to be left out for many hours dependant on how bright the sun is.  It’s not a great method in the UK when we don’t get that much powerful sunlight.  If you try it it’s best to filter the water first (see above) to make it as clear as possible so the sunlight can penetrate into the inner fluid.


One can also collect clean water from a source even more direct than a spring – rainwater.  Try to create a funnel and the larger the mouth of the device the more rain you’ll collect and the faster you’ll fill your containers.   I often rig my shelter tarp to have one corner slightly lower than the rest and place a bottle under it.  So as I slumber in the rain trickles down the shelter into the bottle and my water stocks are replenished.  A pieces of string draped from the corner into the bottle can help direct flow more accurately even if the tarp is buffeting.


So it’s all really common sense.  All these ideas can be applied even if you have chemical and water purification devices as it’s always best to start with the cleanest water you can.


I’ll talk through gadgets and technology you can use to purify water next week.

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