Of course, you can also use your camp stove to purify water easily, although it takes a little time and you’ll need to carry extra fuel, just in case. To purify water by boiling, bring tainted water to a rolling boil inside a pot for one minute, or three minutes if you’re located above 6,500 feet elevation. It’s easy to boil water to kill impurities, but it does have drawbacks, like the time and effort required to boil the water, and the extended wait time for the water to cool. Ultraviolet light purifiers are also quite quick and efficient, and don’t require you to have a filter along. However, they require batteries, which can die on you at inopportune times. Also, you’ll need to give tainted water multiple treatments if you’re trying to purify large quantities.