Water Purifiers

Editors’ Choice 2021: MSR Guardian Gravity Purifier

Set it and forget it with this gravity-powered water purifier.



1lbs. 3oz.

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Filtering water often starts with drawing straws. Then, the unlucky one gathers vessels, makes the trek to water to pump-and-futz, and lugs all that clean drink back to camp. Sorry, loser! With the Guardian Gravity Purifier, however, everyone wins.

Fill its 10-liter reservoir (conveniently labeled “Dirty Water”), hang it on a branch (or as high above the filter and bottle adapter as you can), loosen the hose clamp, and let gravity do its thing.

“I was impressed with its simplicity and how well it performed,” said one tester who packed the filter on a nine-person rafting trip in Utah’s Cataract Canyon. “I loved that I could fill the bag then have water at camp for the night for our whole crew. It was integral to our trip.”

The Guardian Gravity’s two-stage filter purifies water and eliminates foul tastes. A .2-micron hollow-fiber filter nixes viruses, bacteria, and protozoa, while an activated carbon stage reduces bad taste, chemicals, and heavy metals.

Essentially, this takes everything we loved about the original Guardian, a 2016 Editors’ Choice winner itself, and makes it effort-free. And, while still not cheap, it costs $100 less than its predecessor.

While it shined in a larger group setting, the Guardian Gravity is packable enough for long-haul backpacking trips. Our Editors’ Choice team enjoyed filling bottles at leisure while cooking and debating the merits of various dinner entrees. MSR claims a flow rate of one liter every two minutes. We clocked it at 2:30, but what’s half a minute when you’re sitting around digging the view while the Guardian Gravity does all the work?