More than war, politics, famine, natural or man-made disasters, according to the UN, the number one threat in undeveloped and developing nations, as well as a few developed nations is water that is not safe to drink.
In fact, there is a direct correlation between life expectancy and access to safe water; merely having water is not sufficient, it also must be purified of viruses, bacteria, parasites and harmful chemicals.
Normally, most of us do not have to worry about our water.
In a survival situation, though, all bets are off. One of the most challenging aspects of hurricane Katrina relief was making sure the victims had clean drinking water, for example.
In a wilderness situation, it is even more of a challenge as just about every body of water has some critter lurking in it.
To see several methods of purifying water, check out the next page.