Another way this comes in handy is when you are filtering water with lots of silt in it. After a lot of use in this fashion, the filter can become clogged. This will make it more difficult to pump water. Your arm will tire out very fast if this is the case! With a spare on hand, you can just lock it right into place saving you a lot of effort and giving you more time to enjoy your trip.

One should always use filters before drinking any water source in the wild. A mountain stream may look cool and refreshing, but that water must come from somewhere. Even in the coldest, most appealing stream thousands of microorganisms including bacteria and protozoan thrive. These include Naegleria fowleri, also known as the brain eating amoeba. This organism is found in warm lakes and can take up residence in the human brain. In the past ten years, 23 people have died from exposure to this creature. I have a friend who contracted another organism called Giardia lamblia. This creature causes persistent intestinal issues. Always use proper sterilization techniques when out in the wilderness. These creatures are real and dangerous, but easily avoidable.