If you’re a traveler, a camper, or an outdoor enthusiast, you may often find yourself in bizarre situations, stranded in strange places with no access to food or water. Humans can survive without food longer than they can without water. Your best bet against death or dehydration would be to find, filter, and purify water- from a stream or river if you’re lucky- that you access. To know how to purify water is no rocket science, it involves basic apparatus or tools, and can be done by almost anyone.