MSR Guardian Purifier – Top Notch Water Purification for 5

Austen Beason

As a gear tester and multi-sport outdoors-person, I’d like to think I get my hands on quite a bit of different gear throughout any given season. Some of it is, well, “meh,” other items are cool but too niche functionally, but a good portion of what’s available out there is pretty good quality and will perform to the standard the vast majority of people actually need it too. In other words, it seems increasingly rare for me to come across a piece of gear that really stands out to me when there are just so many good products out there. Well, Mountain Safety Research sure surprised me with their Guardian Purifier $349, their top of line water purifier, which I thought was pretty special that a water purifier could elicit excitement.

MSR Guardian Purifier

MSR Guardian Purifier

I was able to test the Guardian out over several backpacking trips and long day hikes, mostly in the canyon country of Colorado’s western slope, and usually the primary filter device for group sizes of just me to up to 5 thirsty people. Water quality varied from picturesque, clear mountain streams, to questionable, film-covered potholes, and typical muddy, desert water, often with a healthy dose of riverside cow manure for good measure. After pumping about 75 liters through the Guardian, I’m pretty sold on it, and if it means anything, I’ve not gotten sick yet!


MSR Guardian Purifier - Top Notch Water Purification for 5 1Guardian™ Purifier | Filters & Purifiers | MSRVerified BuyerVerified Buyer

 

 

 

 

 

 

 

 

 

 

 

 


Out of the box, the first thing I noticed on the Guardian is its size and stout feel. From the MSR’s website the Guardian weighs in at 17 oz., and I measured its dimensions with the intake hose coiled/packed at 8.20” long and 4.75” at its widest (foam pre-filter to pump handle), making the Guardian, well, not the lightest or most compact purifier out there. Holding it in your hand this thing feels really solid, unlike most portable water filter systems which usually feel like one overly-zealous pump might snap them in half, not so with the Guardian. The trade-off for some extra carry weight/size though is a sweet pumping experience and unbeatable reliability.

Threading compatible with Nalgenes

Threading compatible with Nalgenes

I’ll admit it, I kind of have fun filtering water with the Guardian, which is a huge departure from all of my past backpacking filter experiences where filtering is usually a long arm-tiring chore to be endured.  On MSRs website, the Guardian’s spec page claims a pumping rate of 2.5 liters/minute, which it turns out is much faster than most other handheld filters out there, and on the few occasions, I timed myself I found I could casually fill a one-liter Nalgene in 30-35 seconds affirming their pump rate claim. On the Nalgene note, the Guardian is able to mate with most wide-mouth Nalgene threads so you can simply attach your Nalgene bottle to the filter and not have to worry about spilling it. Additionally, the pre-filter on the intake hose has a clever L-shaped design so that the foam float aims the intake down into the water which equates to way less fiddling with the intake hose to make sure it’s still in the water and not just sucking in air. It’s a small detail, but I appreciated it.

MSR Guardian Purifier

Another detail you might have noticed when checking out the pre-filter is the second hose. As it turns out the second hose is the out-take of one the Guardian’s most unique features, a built-in backflush. For every pump cycle, 10% of the intake water volume is used to back flush the Guardian’s filter cleaning it in the process, dramatically increasing the filter cartridge’s lifespan and all but eliminating the need for filter field-maintenance. Due to this feature, MSR estimates a filter lifespan of 10,000+ liters before replacement. I did a little fun math on that; one person could filter 4 liters of water every single day for 7 years before needing a replacement, whoa. This means no more reverse engineering filter systems in the field to fix a clogged or slow filter, well at least not for the first seven years…

The Guardian's pumping action and clever pre-filter float

The Guardian’s pumping action and clever pre-filter float

As if that wasn’t simplified enough for us, MSR the Guardian does not need to be disassembled when you finish a trip to let the filter dry out like many other filters do, in fact, MSR instructs quite the opposite saying the Guardian filter actually needs to avoid drying out to function properly, so you are better off storing the cartridge with moisture in it. Simply pump the filter till water stops flowing out, and toss it in the closet till next time. Also, if you intend to use the Guardian in cold weather, don’t fret about getting every last bit of moisture out of it before an expected freeze – the Guardian was designed to withstand freezing temperatures without breaking/cracking, however, they do recommend you thaw the filter before the next filter.

All of the previously mentioned features are great, they still fall second to the filter quality, the reason for using a filter at all rather than just drinking straight from the source. Well, as expected the Guardian excels in its filter quality, so much so that it is given the title of purifier over plain filter. If you’re not familiar with the difference, water filters provide protection against waterborne protozoa and bacteria, whereas purifiers provide protection against virus,’ and protozoa and bacteria. While there are several methods of purifying water, the Guardian purifies through the most reliable method, size exclusion, with a filter pore size of 0.02 microns. It is worth noting here that the Guardian is not rated for protection against waters with high concentrations of chemicals and/or heavy metals.


MSR Guardian Purifier - Top Notch Water Purification for 5 2MSR Guardian Purifier | REI Co-op $349.95

 

 

In my testing, no matter how muddy the source water was, the filtered product always turned out clear and without ‘extra’ flavors. At most, the water would filter out a little aerated or foamy, but this I think was mainly cosmetic, a side effect of the small filter pore size and pumping pressure. Furthermore, due to the backflush feature I never noticed any slowing in pump rate due to silt clogging, though in some of the muddier waters it did help to wipe off the pre-filter occasionally.

Testing out the Guardian on some more 'questionable' waters

Testing out the Guardian on some more ‘questionable’ waters

What more can I say? MSR really nailed it with the Guardian Purifier. It provides an incredible level of filtering protection, superb durability, requires almost no maintenance, and can crank out water fast enough for even the largest groups – you might stick to the kitchen sink if the Guardian isn’t fast enough for you, although it might still be cleaner than the kitchen. I would recommend the Guardian to any person that needs absolute reliability in a handheld device for extended, remote, international, and/or larger group trips. That being said, the Guardian is still a lot of filters and the price tag reflects it; the Guardian might be a bit overkill for the standard overnight trip with good water sources, those who are trying pack way light, or people on a budget. Still, if you’ve got the means, this might very well be the only filter you’ll ever buy with a 10,000-liter lifespan, it will handle just about any adventure you can throw at it, and of all the things worth carrying the extra weight in, I’d put water filtration at the top of the list. So, go get out there, explore, and once you’re thirsty the Guardian will be there.

 

If you want to check out the Guardian’s specifications for yourself, here’s a link the MSR’s webpage https://www.msrgear.com/water-treatment/filters-and-purifiers/guardian-purifier/02370.html.

 

Austen Beason

Austen Beason

A transplant of the Midwest, Austen immigrated to the promised land of western Colorado in 2012 in search of good climbing, deep snow, quality rivers, and a college degree when his goofing off allowed. He learned pretty quick the difference quality gear can make on the outcome of a day (or days) in the mountains and began looking for the best gear to abuse.

Austen Beason

In the summer Austen is an avid whitewater kayaker, bouncing his boat down the steep, rocky waterways of Colorado, trad climber in search of the route less traveled, and works as a federal river ranger along the Gunnison River. During the winter Austen spends his time telemarking around the backcountry of western Colorado and working as a ski patroller up on the continental divide.

Austen Beason

Austen Beason

Austen says, “A hundred days of skiing and paddling each per year and you’ll figure out what is wrong or right with your equipment, especially when your lively-hood depends on it.” Austen also has his American Avalanche Association Professional Level 1 avalanche certification, EMT-B, and ACA swift-water rescue cert, as well as a member of the Search and Rescue team in Gunnison County for 6 years.

 

About The Author

Hey, I am Sean - the co-founder of Engearment. We focus on mountain based gear - camping, skiing, splitboarding, snowboarding, hiking, etc. and a strong connection to the community. I am also a fitness professional - having created the Mountain Fitness School and building several fitness facilities around Denver. My heart is always in the mountains and I will do everything I can to help you get the right gear, train well and enjoy being outside. https://mountainfitnessschool.com/p/mountain-fitness-training-get-in-peak-backcountry-condition-using-kettlebells-and-trx

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