The 8 Best Water Filters for Backpackers

Ultralight, ultrafast, and ultraeffective—the best new water treatment devices do the job better than ever.

MSR AutoFlow XL

Gear Guide Filters MSR autoflow
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If you need a filter that can handle a lot of people and a lot of abuse, this is it. The AutoFlow XL pairs a hollow-fiber, 0.2-micron filter with a 10-liter reservoir, the largest in the test. Read the full review here.

LifeStraw Flex with Gravity Bag

Gear Review Water Filters Lifestraw
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For the weight and money, there’s nothing more versatile. Use the Flex as a group gravity filter, suck directly from the source in straw mode, screw it to the top of a plastic water bottle with an included adapter, or run it in-line with a bladder. Read the full review here.

Katadyn BeFree 3L

Gear Review Katadyn BeFree
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If you believe time is of the essence, then the BeFree 3L is your filter. Katadyn took its superfast, 0.1-micron, hollow-fiber BeFree filter (which we gave an Editors’ Choice Award in 2017) and packaged it with a 3-liter gravity setup that includes a hose and hanging strap. The result: the same effortless filtering as the original, but now with increased volume. Read the full review here.

Sawyer Micro Squeeze

Gear Review Sawyer water purifier
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Want a no-fuss filter that weighs next to nothing? Sawyer trimmed what fat there was from its Mini Squeeze system, making the 0.1-micron, hollow-fiber Micro Squeeze filter an ounce lighter and cutting weight from the included drinking pouch (now only .5 ounce). Read the full review here.

Katadyn American Red Cross UltraLight SteriPEN

Gear Review: Katadyn American Red Cross UltraLight SteriPEN
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When it comes to simple water treatment, this is as close as it gets to waving a magic wand. Water-activated sensors automatically turn on this UV purifier, which neutralizes viruses and bacteria in 1 liter of water in 1 minute, 30 seconds. Read the full review here.

LifeSaver Liberty

Gear Guide Lifesaver Liberty
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When turbid, contaminated water is your only option, you can rely on the Liberty. It’s the only filter here that removes viruses (thanks to its 0.015-micron pore size), and it’s the only purifier here that doesn’t require prefiltering if you want clear water. Read the full review here.

H2gO Purifier PRIME

Gear Guide H2gO purifier
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This device is more fun than a kid’s chemistry set. Use water and salt (provide your own) to make a saline solution, add it to the PRIME, wait for a chemical reaction to create a chlorine blend, add it to a bottle of untreated water (clear or turbid), shake, then wait 30 minutes. Read the full review here.

Roving Blue O-Pen

Gear Guide: Roving Blue O-Pen
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If James Bond ever needed to purify water, this is what he’d pull from his tux. It’s the first portable purifier we’ve seen that uses ozone, which kills bacteria and viruses, and has the added benefit of neutralizing taste. Read the full review here.

Staying on route, avoiding bugs, your partner’s overloaded pack: you have enough to worry about without fretting over your water’s safety. Keep it clean the easy way with these eight filters and purifiers, which keep pathogens and contaminants out of your bottle–and out of you.