How We Tested Backpacking Water Treatments

By Amber King, Jessica Haist, and Trish Matheny

Where We Test

To create the best review of backpacking water filters and treatment methods, we carefully researched and chose top models and then put them up to a series of rigorous tests. We polled other backcountry enthusiasts, including Appalachian Trail and Pacific Crest Trail thru-hikers, to see what treatment methods they chose to carry with them in the backcountry for months at a time. Then, we brought them with us in the backcountry on multiple overnight camping trips over several seasons of use. We also took eligible products fastpacking on 20+ mile missions that involved camping in between. With this information, we determine their worth in real-world situations, passing on our observations, comparisons, and recommendations to you.

backpacking water filter - each filter was rigorously tested through a series of at-home... — Each filter was rigorously tested through a series of at-home objective tests and in-field experience. Our review is hands-on, unbiased, with testing that puts each filter we've bought through the wringer.
Credit: Amber King

Testing Metrics

Water Quality

Based on the manufacturers' specifications, we evaluated which filters were effective against certain contaminants. The main difference is whether they treat for Cryptosporidium and if they can purify viruses. We also looked to see how well systems rid super-dirty water of particulates. We did taste tests and tested each system in both clear and exceptionally turbid (water with lots of sediment) sources. We also tested different systems in a “sludge slurry” to see how each fared.

backpacking water filter - the "sludge mixture" is a bunch of potting soil filled with... — The “*sludge mixture*” is a bunch of potting soil filled with pesticides and growth enhancers dissolved in water. We then pumped and filtered this water through each system to see which could handle, and what the water looked like. Many didn't make water we would drink...while others did.
Credit: Amber King

backpacking water filter - a look at just one of the test results. to the left, we see the... — A look at just one of the test results. To the left, we see the Grayl Geopress which completely purified the water. It was rid of smells and everything else. While the MSR Mini works EX (and all other filters) filtered out the soil, they left it yellow and still smelly.
Credit: Amber King

Durability, Construction, and Maintenance

We did rigorous field testing and put each product to the test for durability with regular backcountry use to see where these products fail with use. We also researched online by reading product reviews to see if there were trends in products based on other users.

backpacking water filter - hand pump filters like this one easily come apart and are... — Hand pump filters like this one easily come apart and are field-serviceable. We took the time to assess which could easily be cleaned and cared for in the field, and which we would leave at home.
Credit: Amber King

Treatment Time

We time-tested each product by filling a liter bottle. We took three trials for each and averaged the test results. Some systems offer water on the go, so for each of these, it was deemed “instantaneous.” Pump filters were also a little subjective, but we had the same tester do all pump filters at a similar rate of “pump.” This helped to decipher which ones were able to intake more water and move it through the filter.

backpacking water filter - we pumped, filtered, and purified 40l of clear water in this sink... — We pumped, filtered, and purified 40L of clear water in this sink test to see the time it took to attain 1 liter of water. We looked at the deviation from the average to determine which constantly needed cleaning (yes, even with clear water), and which kept performing.
Credit: Amber King

Weight and Packability

We did not take the manufacturer's word for it in this department. Instead, we tested these products on our scale with all the components we would want or need in the backcountry. We also look at the profile of each product. We also stuffed each into a backpack, pockets, and hydration vests to see how they felt to carry for long distances.

backpacking water filter - we take the katadyn befree on numerous trail runs in the mountains... — We take the Katadyn BeFree on numerous trail runs in the mountains because its the lightest and easiest on-the-go filter to drink from. We tested each filter and purifier by carrying them on backpacking trips, weighing them, and evaluating how each carried inside or outside a backpack.
Credit: Amber King

Ease of Setup

In this metric, we consider what you have to do to get water. Does it work on the go, or do you need to set up a system, like a gravity filter? We also note how well a system can pull for different water sources in this category. To test this, we tried each in the field with varying environments, including steep banks, tiny puddles, and flowing streams.

backpacking water filter - how easy is it to collect water and set-up your system? for each, we... — How easy is it to collect water and set-up your system? For each, we took water from lakes, streams, and rivers to learn about the best use case scenarios and which took the least time from our travels to filter water.
Credit: Amber King

Ease of Filtration

In this metric, we note how easily water goes through the system. In these tests, we noted the amount of effort required to filter water. Did you have to use muscle to pump it through a filter or sit back and wait? We also note if parts are easy to lose in this metric.