Water filters can’t eliminate viruses like water purifiers. They can only remove sediment, debris, bacteria, and protozoa. Purifiers, on the other hand, can cleanse your water of viruses that are small enough to pass through the filter’s pores. When it comes to hiking and camping in North America, a water filter will usually suffice as viruses are quite rare. However, when you’re going abroad, it’s best to have a water purifier with you to ensure safety.