When it comes to water purification, there's four main ways of achieving it which includes using heat, filtration, chemicals, and ultraviolet light. Personally, I think it's a good idea to use two methods when using water that's found in the wilderness. I prefer to first filter my water to remove impurities from the water, and also treat it with either heat, chemicals, or UV light to ensure that all any biological contaminates are eliminated.
There are a lot of water filters available that are designed to be carried with you for backpacking and similar adventures. It would be a good idea to have on of these in your
bugout bag
, or
survival supplies
. When choosing a filter it is best to have one that filter at least at a 2 micron level so that it protects against Giardia and Cryptosporidium. A really cheap filter that I've used before and does the job is
Coghlan's Water Filter
. It is rather cheaply made in my opinion, but if it's all you can afford it's better than nothing. If you can afford it, I would recommend upgrading to the
MSR MiniWorks EX Microfilter
or the
Katadyn Pocket Water Microfilter
. Both filter anything bigger than 0.2 microns, are light enough to carry in your backpack. The main difference between the two is that the
MSR MiniWorks EX Microfilter
uses a combination ceramic and carbon filter while the
Katadyn Pocket Water Microfilter
uses a silver-impregnated ceramic filter.
Heat is a good option for killing most biological contaminates. If you can get a heat source to bring your water to a hard boil for at least 5 minutes, this may be a good option. If you are mobile however, this probably won't always be an option. A few other things to consider are that you can't throw your plastic
water bottle
in a fire to boil water, you will need a metal
camp pan
of some sort, and you will want to let your water cool before you put it in a plastic container or
Camelbak
.
UV light is an easy to use option, they make light models like the
SteriPEN Adventurer Opti
that will carry easily in a bugout bag. This water purifier pen zaps viruses, bacteria and protozoa such as giardia and
cryptosporidium with ultra-violet light. To use it, you just press the button, dip the lamp into
your drink, and wait 90 seconds to purify. If you are preparing for the end of the world however, there probably won't be a lot of stores where you can stop in to pick up more
batteries
.
There are a couple of different chemicals that can be used to sterilize water.
Iodine
is a popular chemical for water sterilization, and you can get it in
tablet
or
crystal
form which makes it easy to carry and use. I like the crystals because they can be used over and over again to sterilize thousands of gallons of water. I have however heard of studies which show various health issues caused by long term consumption of iodine, so I don't know if it is the best option or not.
Chlorine is another chemical option. If you are digging in at a survival location, you can stock pile some
regular unscented household bleach
for this purpose. It's cheap and typically only takes 4 drops per quart of water to sterilize it (based on average 5.25% chlorine content). You will need to double if the water is really dirty or extremely cold. Just stir it in good and let it sit for 30 minutes. They do sell
Potable Aqua Chlorine Dioxide Tablets
which make it easy to carry as well.