Backpacking Water Filters

What’s Up With That?


Water filters for backpackers appeared on the market a long time ago. I remember seeing them in the 1980’s, and maybe they have been commonly available longer. At the time I thought, that is a lot of extra weight. Most backpackers are very diligent in keeping their pack weights down, or at least they should be.

I don’t use one and don’t plan on starting. But clean water should be on every hiker’s mind. I also don’t want to minimize the dangers of “cooties” in back-country water sources. There have been numerous studies that show back-country contamination is minimal at best – don’t believe them. There are all sorts of bacteria, protozoa, and viruses just waiting to take a trip through your body. Probably the nastiest we commonly see in the back-country is giardia, which can make some people very sick for a long time. Many “experts” contribute giardia with poor hygiene when hiking or camping. Another factor is that the majority of giardia cases are misdiagnosed or even not reported. A hard protozoa to kill is cryptosporidium (crypto), which causes cryptosporidiosis, another nasty sickness. Crypto can be very hard to kill.

Okay, so the cooties are bad and the filters are heavy (some filter systems are getting reasonably light these days), what is the poor backpacker to do?

You could boil all your water; not very efficient and is time consuming. Boiling water is the most reliable method of purification.

The filter companies want you to buy a filter – lots of money to be made. But there are other alternatives. What the hiker chooses to use should be based on research, not panic and absolute risk avoidance. Aside from the weight of the filters, they can break, plug up, or get damaged from below freezing temperatures. Another option is a UV device that zaps the cooties. But it is an electronic item subject to the usual circuitry failure, stray electrons, breakage, and dead batteries; not to mention they need a rather large wide opening in your water bottle or canteen to be inserted.

This is not meant to be a comprehensive review of the market or what, how, and when cooties can get into your water supply. Now if you are hiking in country that has water sources every 30 minutes, then a light filter might be the lightest option – you just filter the small amount of water you need at each stop. Many hikers do not enjoy this kind of back-country abundance of water. Aside from the reliability issue of filters, you would want the lightest option and carrying a few gallons of water, just in case, would not be one. What follows is what I have used.


So reviewing the above table, iodine is out. It doesn’t kill crypto. I have to tell you that iodine was my only water treatment for nearly 40 years. So either I picked good water sources or was lucky. Probably a little of both. In 2008 I switched to chlorine dioxide because it kills crypto. Don’t worry about taking these chemicals, they are what your municipal water company probably uses to purify you drinking water.

The Aquamira and MicoPur tablets are almost identical. They may even be made by the same company. Also they are several times more concentrated that the Aquamira drops. For the tablets the wait time is:

wait times

Now you might say, “Nick, I’m not waiting 4 hours to drink my water!”

Of course not. You have to plan your hikes. I plan my trips so I will be getting to reliable water sources towards the end of the day. This way I can cook my dinner (boiling water) and drink coffee or water. I purify the water in my water bottles and am not worried about the time, because I will be sleeping while the chemicals do their job.

If there are additional water sources during the day, I don’t need to carry as much water and plan my hiking to get to the water source with a little bit of water left. My strategy is to almost always treat my water for 4 hours. I also  want to minimize the amount of water carried, without dying of thirst, but am willing to deal with a little extra weight without the worry of a failure of the other options.

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