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Field Tested: MSR TrailShot Personal Water Filter

The bikepacker has a myriad of logistics to manage, potable water chief among them. Fail to consume enough h2o and your progress will grind to a parched halt. Drink untreated water and you play a risky game of intestinal Russian roulette. The trick is to balance the need for clean water with an appropriate means to produce it. Fortunately for us, new solutions keep entering the market.

In the last two years MSR has managed to raise the water treatment bar twice. Their impressive self-cleaning Guardian purifier made big waves when it was released and now their newest innovation, the diminutive TrailShot micro-filter, is set to do the same. Although it won’t be available to consumers until January, I was amongst a lucky few to get an early production sample and sufficient time to test it in the backcountry.

At just 142 grams the TrailShot is so light and compact it genuinely qualifies as pocket-size. With only one short length of hose fitted with a tiny pre filter, it’s also extremely easy to use. Just plop the hose in any water source and squeeze the silicone bulb built into the body of the filter. As clean water squirts from the other end, the user can either drink directly from the conical mouthpiece or use it to fill bottles and reservoirs.

Capable of removing bacteria, protozoa, and particulates, the TrailShot employs MSR’s proprietary Hollow Fiber technology similar to that used in their HyperFlow, and AutoFlow systems. Back flushing the TrailShot is as simple as giving it a few sturdy shakes and the maximum capacity of the replaceable filter element is a respectable 2,000 liters. Best of all, the $49 retail price makes this a very affordable filtration solution.


Given its size, I didn’t expect the TrailShot to live up to its claimed liter per minute flow rate, but I was pleasantly surprised to see it did. Priming requires only a few gentle squeezes and the effort needed to keep water flowing is minimal, even for tired hands. The short hose creates a bit of a challenge with some water sources, but my work around has been to carry an Ultra-Sil Kitchen Sink made by Sea to Summit which I use to scoop up water, allow sediment to settle, and then do my filtering business under the comfort of a shade tree.

So, how does it really work? Being a desert dweller, our water sources are few and far between, many of them lovingly referred to as cow tanks for obvious and unfortunate reasons. They have the appearance of the chocolate river in Willy Wonka’s factory, but that isn’t chocolate floating in there. Such water sources demand a filtration system lest you be forced to chew your water, but their high turbidity is a nightmare for most filter elements.


To see how the TrailShot would handle gnarly water, I took it to a murky tank and prepared myself for inevitable disappointment. After collecting and decanting roughly eight liters of water for half an hour, I dropped the TrailShot’s hose in the top few inches of the water and started pumping. Almost immediately I could feel the sediment working against the Hollow Fiber element. I gave it a few shakes and resumed filtering. By the time I got to the final liter I feared I may have killed the little bugger.

I was eventually able to pump clean water through the filter while giving it repeated shakes. That seemed to restore it to the normal flow rate. Suffice it to say, Willy Wonka water is tough for the TrailShot, but that’s true of nearly every system I’ve ever used save for a few like MSR’s own MiniWorks EX with its ceramic filter. On the upshot, the TrailShot’s filter cartridge is small enough I plan to carry a spare in the future just in case one gets irreparably clogged.


MSR is quick to point out they designed the TrailShot for backcountry athletes like through-hikers, trail runners, and mountain bikers. In that capacity, provided you have abundant water sources to dip into throughout the course of your journey, the TrailShot is a near perfect product. Far superior to any straw style filter I have ever used, its ability to fill additional containers is an obvious bonus. For those routes that require high volume pumping sessions once or twice a day, particularly in environments with turbid water, this may not be the ideal solution. For most other scenarios, I can see the TrailShot quickly becoming a bikepacker’s favorite.


Weight: 142 grams (5 ounces)

Flow Rate: 1 liter per 60 seconds

Capacity: 2,000 liters

Effective against: E.Coli, Salmonella, Giardia, Cryptosporidium

Price: $49

Dimensions: (LxWxH) 5 x 2.5 x 2

Place of manufacture: USA

Contact: msrgear.com

Standout features: compact size / ease of use / flow rate


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Christophe Noel is a journalist from Prescott, Arizona. Born into a family of backcountry enthusiasts, Christophe grew up backpacking the mountains and deserts of the American West. An avid cyclist and bikepacker, he also has a passion for motorcycles, travel, food and overlanding.