Clean water is essential to human survival, and the fact that so many countries lack access to safe drinking water is one of the great tragedies of the modern age. However, knowing how to purify water, whether for day to day use or for camping and wilderness expeditions, can make the difference between life or death — quite literally. Here are three great and easy ways to purify water that everyone should know.


1. Heat


The most common way to purify water is by heating it. By heating water to near boiling point and letting it simmer for 10-12 minutes, you can destroy most of the bacteria and other microscopic organisms involved. The amount of time required to kill all the organisms will differ based on your elevation. Note: if you’re unable to heat the water, leaving it exposed to sunlight for an hour or more will kill a majority of the pollutants inside.


2. Filtration


If you’re stranded in the forest, laying three clean shirts on top of one another and pouring the water through them into a container will work to purify it. This method won’t destroy bacteria, but it will remove physical pollutants and algae from the water. After this is done, heat can be applied to make the water safe to drink once more.


There are also mechanical filtration machines that are more effective than the t-shirt method. These machines pump the water through a powerful filter that cleans it of any debris and algae, but does not disinfect it.


3. Chemicals


Placing a 2% iodine tincture inside a bottle of water will purify it of any organisms living within it; however, this will change the color and taste. While it is harmless, some may find it unpleasant. Another way of cleaning the water is through chlorine dioxide tablets. Once used, these take around four hours to purify the water, but leave no after effect or smell. However, they must be used with care, as too many may lead to a lethal concentration of chlorine.


Although it is unlikely that anyone living in the modern world would find a need for water purification techniques, it is important to know how to gain access to clean water should you ever find yourself in a survival situation. These three techniques will provide enough clean water to sustain life until someone is able to reach civilization. However, they are not the only techniques for purifying water; there are many others out there that may be of use.