Water Purification

I had a friend ask for a ‘pros and cons’ list for water purification for day hikes and backpacking, thought I’d share it here.

I go round a tree about this, I used tablets for a long time because I could not decide on a system and most of the time, we just day hiked or camped where there was potable water, so it wasn’t much of an issue.  We barely used any of them before they expired.

Most water-borne illnesses present as vicious diarrhea and vomiting.  They can take weeks to percolate in the gut and can lead to some amazing weight loss stories of 10+ pounds in a week.  So treating water isn’t optional.  Moving water does not equate clean water, despite how many people like to say it does.  Treat all water in the backcountry.  BUT AND HOWEVER: if in a survival situation in which drinking creek water will ensure life long enough to walk out or be rescued, drink it.  In all other situations, plan ahead and have a system in place.

There are pros and cons to each system:


-easy to use
-most folks bring along a few for emergency backup no matter what system they choose

-if they get wet, they are done for.
-wait time between scooping the water and using it
-makes the water change color, can be neutralized to clear, that step adds more time
-takes 4 hours to kill cryptosporidium  (chlorine tablets)
-iodine tablets do not kill crypto at all

-catch bacteria and protozoa
-lightweight (ish)
-some types can screw right into a water bladder line or water bottle which means the time from scooping water from a creek, replacing the filter and drinking takes basically seconds
-gravity fed systems, once the water is gathered and the proper height branches are found to hang it, do all the work themselves, feeding the water from the dirty bag through a filter to a clean bag hung lower down.

-the inside of the filter stays damp if stored for weeks between use, extra steps are required
-useless if frozen, even thawed back out, the filters are probably damaged and should not be used
-can clog in the field, additional equipment must be brought along to backflush
-in squeeze systems, the squeeze bag can burst.  Extras are not optional
-does not affect viruses unless it has an iodine filter, so in areas of agricultural or household runoff, a secondary chlorine tablet system needs to be used


-Kills bacteria, protozoa, and viruses
-if water is silty, the boiling will make the silt drop to the bottom, leaving the clean water at the top, which is nice!

-heating the water uses fuel and time
-the water is ‘flat’ after boiling and at least needs to be poured back and forth between 2 containers a few times to get some air back in it
-waiting on the hot water to cool enough to drink.
-This is a do-ahead chore for sure, pretty much ensuring the whole next day’s allotment of water will need to be toted the whole next day to keep from having to stop and boil water at each refill point.

UV light

-works fast=90 seconds for a liter
-neutralizes bacteria, protozoa, and viruses

-runs on batteries, always need spares
-will only fit in certain water bottle openings
-the long glass tube to consider at all times during use (don’t drop it!)
-will not work in cold water, time must be added for the water to warm up
-sediment must be prefiltered (pour through a bandanna)
-90 seconds per bottle times 6-7 bottles a day can add up in time, that’s 20 minutes a day for 2 people just in ‘the light is on’ time.




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