According to the United States Environmental Protection Agency, 90 percent of the world’s water is contaminated in some way. It could be from bacteria, disease, pollutants, chemicals, parasites or toxic minerals. Surface waters are partly made up of rainwater and runoff, so any pollutants in the air or on the land become part of the water system. An outdoorsman should never drink water he finds as is, unless it is a dire emergency and the danger levels outweigh the risk.
Strain the water through a cloth or bandanna to remove the largest sediments, or let dirty water settle overnight and remove the clean water from the top.
Punch five to 10 holes in the bottom of a can. You can also use a small cone made of bark with a small hole at the bottom, tied together with a rope or string.
Place some stones, nonpoisonous grass or breathable fabric over the holes. Add a layer of gravel on top.
Crush some charcoal from the fire into small pieces and place it over the gravel. Cover over it all with a layer of sand.
Pour water into the filter and catch the clean water in another container. Repeat the filtering process until the water looks clear.
Bring the water to a boil and continue boiling for about one minute. This will kill most pathogens and purify the water.