At roughly the size of a 1000ML Nalgene bottle, with a fill-up time of fewer than 30 seconds, the MSR Guardian Purifier water filter might just be the best filter on the market for all bicycle-related outings, yet it will cost ya… Let’s take a look at this game-changing filter in detail below.
The Guardian weighs in at 1lb 2oz, or about 510 grams, with its carrying bag and instruction manual as shown but that weight is mostly due to its heavy-duty ceramic filter. This ceramic element meets NSF protocol P248, a testing standard used by the U.S. military, for the removal of viruses, bacteria, protozoa, and sediment from “worst-case” water conditions. That means you can filter silty rivers, shallow vernal pools, puddles, mud bogs, and everything in between. With rampant cattle grazing across public lands, many once potable springs have been contaminated with feces and urine. Fear not, for this filter removes all microbes (and even most of the taste) from the water.
With a rate of 2.5 liters per minute (!!!!) you can filter your entire riding crew’s water in under 5 minutes. When you look at other ultralight bladder filters like Sawyer and Katadyn, their ability to filter silty water is moot, and due to the design, there is a high risk of contamination. With the Guardian, the 4′ long hose and filter cap ensure no dangerous microbes will enter your water source.
The pump actuation is easy thanks to its two-hose system which purges excess water from the inlet valve, keeping the water flowing with each pump. Other filters tend to clog up, drastically reducing filtration time and quantity. We were amazed at the speed the first time we used ours.
On a recent backpacking trip in Canyon Country, this filter topped off our bottles and water bladders in a matter of minutes. Further down the canyon, we filtered small, bubbling seeps in the desert willow. A water source roughly the size of a cereal bowl filled up four 4l bladders with ease.
So there’s gotta be a catch, right? And there is. The Guardian Purifier will set you back a cool $349.95 but if you spend a lot of time in the desert, where water sources are scarce and sketchy, or if you’re embarking on a long tour like the Tour Divide, the Western Wildlands, or the Grand Loop, there isn’t a better filter on the market. They’re also Made in the USA of domestic and imported materials.
We bought ours at full retail and it’s got to be the best investment we’ve made for our backpacking, bikepacking, bike touring and bike camping library.
See more information and videos of the Guardian Purifier at MSR.