The Best Water Filters and Purifiers of 2024: Staff Picks

Our experts share their seven favorite water filters and purifiers for camping, backpacking, traveling and more.

Ebony Roberts| Published March 5, 2024

38 reviews with an average rating of 3.7 out of 5 stars
A backpacker filters water at a stream.

The best feeling after logging miles on foot: quenching your thirst from an icy stream. But drinking from Mother Nature's tap isn't like flicking on a faucet at home. You have to treat the water first, using either a water filter or a purifier to remove harmful contaminants.

A water filter guarantees access to safe drinking water by removing harmful impurities from natural sources like rivers, lakes and streams. Whether you're treating water in the backcountry or on an international trip, a water filter or purifier is an invaluable tool. Carrying one also reduces reliance on single-use plastic bottles by allowing you to fill up a reusable vessel wherever your adventures take you.

You might hear the terms "filter" and "purifier" used interchangeably, but there are subtle differences between the two. A water filter strains out bacteria, protozoan cysts and other impurities. A water purifier removes these contaminants plus viruses, which are often too small for most water filters to catch. (Related reading: How to Choose a Water Filter or Purifier)

Choosing a water filter or purifier is like selecting any piece of adventure gear: There are plenty of products available, but you'll want to pick the one specific to your needs and preferences. We consulted seasoned REI Co-op staffers and combed through customer reviews to narrow down favorite filters and purifiers for everything from camping to international travel. These are their seven favorites.

Staff Picks

Find quick recommendations below or scroll down for in-depth reviews.


The advanced medical-grade hollow-fiber technology in the MSR Guardian is a workhorse purifier. It destroys viruses and filters out bacteria, protozoa and heavy metals. "It's a good option for somebody who's making their way to natural disasters more frequently as part of a response team or who goes into areas of the world where the collection of contaminants isn't as regulated," says Christa Lindsey, a program coordinator at the co-op.

For camping and other trips in North America, it provides more water purification than you'll likely need, and it's a little heavy and bulky to pack. But if you want to invest in a single filter or purifier for both car camping and your emergency kit, the Guardian is a solid choice. "I'm in Utah, and it seems like everyone grabbing one is thinking about that 72-hour emergency kit," says Tim Bird, a department manager at the REI store in Farmington, Utah.

"Speed, dependability, versatility and low-maintenance are why I love this filter," writes one customer-reviewer who's taken the Guardian on hiking trips to Peru and Glacier National Park. It has an outstanding flow rate of 2.5 liters per minute, and one of its most-loved features is that it's self-cleaning. With every stroke, this MSR pump uses 10% of its water to flush the contaminants in its filter back into the source, meaning you never have to deal with backflushing or clogging, all while the flow remains constant. The Guardian's hollow fiber filter should last to around 10,000 liters. When the flow rate becomes compromised replacement filter cartridges (though pricey) are available.

"I am a primary user of pump filters because I spend a lot of my time on glaciers melting snow, and this is the king pump," writes one customer-reviewer, "It takes the cake. It's so fast, and the pump action is very, very smooth." Its rugged construction can also withstand drops from up to 6 feet and freezing temperatures. If you're looking for the ultimate purification system that can work for a little bit of everything—from camping with large groups to adventuring overseas—consider adding the Guardian to your kit. Buy here.

A water filter is a backpacker's best ally for ensuring safe hydration from natural sources—bonus points if it's light, packable and easy to use. It's no surprise that REI staffers who love backpacking have a soft spot for the Katadyn BeFree 1.0 L Water Filter Bottle. This lightweight, collapsible water bottle can filter up to 2 liters per minute and easily fits inside a pack's brain or pockets. To use, simply fill the bottle from a water source and gently squeeze or invert the bottle to begin drinking. Hollow fibers in the screw-top filter prevent harmful particles (which are too big to move through the strands) from entering your drinking water. "I can drink from it as fast as I can squeeze it," says Carlos Rodriguez, a retail sales specialist at the REI store in Wichita, Kansas.

Washing the filter is also a cinch. "Swishing it around in clean water worked for the dirt and grime," says Barrett Deisher, a retail sales specialist at the REI store in Boise, Idaho. "I have about 500 miles left on the AT to finish and will be bringing a BeFree with me." However, a deeper clean can be tougher to achieve because this lightweight filter doesn't have a prefilter or a surface that can be scrubbed. Depending on water quality, the BeFree may need more frequent replacements compared to others on this list. Replacement filters are available, though.

Like other collapsible squeeze bottles, the BeFree can develop leaks or tears. Fortunately, the cap works with other hydration bladders with a 43-millimeter screw top, in the event the bottle begins leaking on the go. The BeFree also includes a cap to help keep the nozzle clean. The streamlined design makes it a solid choice for adventures beyond backpacking, like trail running. "I like that I can put it in my pocket," says Steve Jackson, a retail sales specialist at the REI store in Portland, Oregon. "The wider mouth opening also facilitates easier water collection than other narrow-mouth bags." Buy here.

Cut down your camp chores with the Platypus GravityWorksâ„¢ Water Filter System, a simple and effective kit that uses two hanging bags (one for dirty water, one for clean) and the power of gravity to filter up to 2 liters of drinking water in just over a minute.

"This is by far my favorite water filter I have ever used," writes one co-op customer-reviewer. "You don't have to sit there squeezing or pumping it." Once you add water to the bag and hang it up, you can let gravity do its thing while you focus on setting up your tent or prepping dinner.

"It is an absolute revelation," says Heather Young, senior manager of product copy production at REI, who first used a smaller version of this filter on a multinight trip to carry extra water when sources were scarce. By filtering water into hydration packs and carrying extra water in both the clean and dirty bags, "we were able to set out carrying two times our personal capacity and filtered along the trail when the reserve clean bag was used up," she says.

Around camp, the hanging water filter bags can double as a handwashing, pot-washing or cup-filling station, as well as a camp shower. Backflushing is as easy as lifting the filtered water bag higher than the unfiltered reservoir. "Honestly, we looked forward to the chore of filtering. It was so fast and so satisfying," Young says. When it's time to swap out the old filter for a new one, replacement cartridges are available.

Use the hose or water reservoir to retrieve fresh water; the wide opening makes water collection easy. This size works well for families and groups, and it also comes in a larger version, the Platypus GravityWorks Water Filter System - 6 L for even bigger gatherings: It's the same setup as the 4-liter system but with more water capacity (and a slight uptick in weight and size). Buy here.

Globe-trotters seeking worry-free hydration during their travels should consider adding the Grayl GeoPress Water Filter and Purifier to their carry-on. Water quality can vary depending on your destination, so a purifier is an essential piece of gear.

The bottle construction allows for discreet use (no pumping in public) and fits easily in most daypacks. And because it serves as both your purifier and drinking vessel, you only have to find room in your suitcase for one item. One co-op customer-reviewer used their Grayl GeoPress on a two-week trip to Nepal: "I filled up in airport taps, street lines, mountain streams, hostel sinks and countless other questionable taps that even locals warned me against using. Every single drop of water from this bottle tasted like pure, clean filtered water."

Filtering water with the GeoPress can take a little practice. It requires filling the bottle from a water source, placing it on a firm surface (like the ground) and pressing the top down to force the water through the bottle. When the filter's cleanest, it can purify 24 fluid ounces (or a little less than a liter) of water in eight seconds. The GeoPress purifier cartridge will need replacing after around 350 cycles (about 65 gallons) or whichever comes first—when the press time exceeds 25 seconds or three years since the first use. Stashing a replacement cartridge in your luggage takes up minimal space and offers a backup.

"I wasn't sure when I bought the GeoPress that I would have the strength to use it," writes one REI customer-reviewer with arthritis. "However, I used it for two weeks in India, and it worked well beyond my expectations. I figured out how to press it properly, [and there was] no strain on my joints. The water tasted great, and I felt great for having mastered it."

Another popular feature is the one-way drink mix valve that lets you add electrolytes or flavored drink mixes to your purified water. The GeoPress can also withstand rough handling and drops from up to 10 feet. Buy here.

Cooking for a large group at camp can be time consuming, but filtering water for everyone doesn't have to be thanks to the MSR Auto Flow XL Gravity Filter. "This is a wonderful filter to take with a group or when you anticipate needing a lot of water," writes one co-op customer reviewer. "It filters quickly, it's easy to set up and use [and] I like being able to fill the bag and walk away as it fills our water bottles."

Unlike some gravity-filtration systems that rely on two bags—one for dirty water and one for clean—the AutoFlow XL has one large reservoir to hold unfiltered water, plus a hose (outfitted with a hollow fiber filter) that connects directly to a water-bottle attachment. The included attachment can fit most wide-mouth water bottles. The hose detaches easily, so you can store extra water in the bag.

The AutoFlow XL is constructed from a rugged, tear-resistant material and can be cleaned in the field. To help prevent clogging, there's a sediment trap in the bottom of the bag—though it does take some practice to learn how to use and clean it properly.

Just make sure you know how to remove any air bubbles—air that becomes trapped in the purifier cartridge can reduce flow rate. To remedy this, hold your cartridge horizontally and tap it to release the air. "This water filter system is absolutely flawless once you learn to clear bubbles," says one customer-reviewer who used the AutoFlow XL on a six-day trip to the Boundary Waters Canoe Area Wilderness in Minnesota. A built-in sediment trap prevents large particles from entering the filter. Buy here.

Whether you add them to a home emergency supply or include them in your backpacking kit, the Potable Aqua Iodine Tablets are a great option should anything happen to your primary filtration method or water source. "When I'm relying on a UV filter in the backcountry, having the PA tablets as an option is important," says Michelle Trame, senior user experience designer at REI. "If I run out of battery [on my UV filter] or can't access water without sediment, I may need another solution."

The tablets are also useful during disaster relief and other unexpected events. When stashed in an emergency kit, an unopened bottle of iodine tablets can last for up to four years. The drawback: They don't work as quickly as a filter. "The time it takes for the iodine to get the job done [can be] 30 minutes depending on water temperature and quality," Trame says. They can also give water an astringent taste. That time frame is still significantly less than other tablets, like chlorine dioxide, which can take four hours or more to purify water. And the iodine's distinct and unpleasant flavor can be combated with taste-neutralizer tablets. If peace of mind is what you're after, the taste can be overlooked.

"While the iodine taste isn't as nice as fresh mountain spring water, I've found that I don't actually mind it and stopped using the PA neutralizer tablets," says Trame. Buy here.

Buying Advice

Water Filters vs Purifiers

Before you buy a water filtration device, you need to determine whether you need a filter or a purifier. The main difference between a water filter and a water purifier is the size of the microorganism each combats. (Related reading: How to Choose a Water Filter or Purifier)

Water filters work by physically straining out bacteria (such as E. coli, salmonella, campylobacter and shigella), protozoan cysts (such as cryptosporidium and giardia lamblia), and other impurities and debris that could be harmful or affect the taste, odor or appearance of the water. "A filter will take care of most of the stuff that you're going to face in the U.S. and North America if you're camping, backpacking, or hiking," says Christa Lindsey, a program coordinator at REI.

Water purifiers "take care of all of those same things plus viruses," Lindsey says. They eliminate microbes that are too tiny for most water filters to catch (such as hepatitis A, rotavirus and norovirus). "If you're traveling internationally or to areas of the world where you're concerned about fecal contamination of the water from a human source, that's where you'd really want to focus on having a purifier, not a filter," says Lindsey. They're also ideal for natural disaster response and emergency preparedness. (Related reading: How to Maintain Your Emergency Kit)

Types of Water Filters and Purifiers

Water filters work using different mechanisms depending on their type.

Mechanical filtration, sometimes called physical filtration, refers to water passing through an internal element or cartridge with microscopic pores that catch debris, protozoa and bacteria. This method physically strains out particles and larger impurities by forcing water through a physical barrier, often made of paper, ceramic or specialized hollow-fiber membranes. Over time, strained matter clogs up a filter's pores, requiring it to be cleaned and eventually replaced.
Some common mechanical filtration types are:

  • Pump filters work by physically forcing water through a filter medium, typically using a hand-operated pump mechanism. Pump filters allow you to filter only the water you need, and they're good for processing large volumes of water. But pumping can be a chore, especially at the end of the cartridge's lifespan.

  • Gravity filters utilize the force of gravity to pull water through a filter. Most models come with a pair of reservoirs and an inline filter. Dirty water stored in the higher-hanging bag flows through the filter into the clean reservoir. These are convenient for filtering larger quantities of water without much effort, but you need a place to hang the setup and a water source deep enough to fill the bag.

  • Straw or squeeze filters work by forcing water through a filter, either by squeezing water through a filtration system or by directly drinking through a strawlike device that contains a filtering mechanism. They are ideal for individual use, and they're usually lighter, more compact, and cost less than pump or gravity filters. However, they require more cleaning in the field. With some straws, you can only drink from the source and can't store any water.

  • Bottle filters and purifiers have built-in mechanisms that allow you to fill the vessel with dirty water and drink clean water through a spout, just as you would with a regular water bottle. Some use the suction provided when you sip from a bite valve to filter water, while others work like a coffee press. They offer quick access to drinkable water and are light and easy to pack, but water quality is limited by bottle size and they require field-cleaning.

Chemical purification like chlorine dioxide tablets or iodine can effectively neutralize microorganisms in water, killing viruses that are too small for most filter elements. They are lightweight and portable but require waiting time for the chemicals to take effect. Iodine has a very distinct aftertaste that many people don't like, especially if you're drinking in large quantities over a long period. You can add some taste neutralizers, but there's still an aftertaste, which is why some people prefer chlorine dioxide (though this method takes longer to clean the water and has a shorter shelf life). Chemical tabs are great as a backup to other filtration systems or stashed in an emergency kit.

Activated carbon filtration uses carbon to soak up industrial chemicals, heavy metals, pesticides, and other contaminants. It can also neutralize bad smells and taste.

UV purifiers are pen-like devices that use ultraviolet light to disinfect water, destroying bacteria, viruses and other microorganisms without physically removing them. They are typically compact and easy to use but rely on batteries or a power source.

Ease of Use

Ease of use is an important factor to consider when choosing a water filter. "Some are really simple," Lindsey says. For example, "If you've ever used a sports cap type water bottle, you'll know exactly how to use a water-bottle-style filter or purifier, and it'll be easy to use, " On the other hand, "some require more technical skills and prior practice. You may have to learn how to prime it or how to take it apart in order to backflush it while you're out in the field," Lindsey says.

Ultimately, you want a filter that you feel comfortable and confident using—and some filters may require more practice and education than others before you head into the backcountry with them.

Capacity and Output

Capacity refers to how much fluid your filter can hold (if any), and output denotes how quickly it can clean the water. The Platypus GravityWorks Water Filter, for instance, holds a lot more and cleans quicker than, say, the Sawyer Mini Water Filter. But the smaller filter may make more sense if you're embarking on a one-night solo camping trip.

When choosing a filter, consider your group size, trip duration and activity. "Think about how many people you're filtering water for and how frequently you think you'll need to filter water," says Lindsey. "Are you going on a longer trail run day and just need to filter water for yourself a few times along that run? Or are you backpacking with a group of scouts and looking to filter water at the end of the day for a large group?"

(Related reading: Hydration Basics)

Portability and Weight

How you plan to use your water filter will significantly determine its size and weight. Considering your intended usage is key; for a small-group backpacking or hiking trip, prioritize a compact filter that fits snugly in your pack and is field-maintainable. Larger groups may want to focus on flow rate and capacity over weight savings.

Typically, a larger, heavier filter will be able to move more water through it faster because its filter element can hold and move more volume compared to a smaller one, says Lindsey. A smaller filtration device will often be lighter and more compact—but this comes at the expense of output. "Because it's smaller, there's just less surface area for the water to move through that filter," Lindsey says.

Durability and Longevity

Consider the durability of the filter as well as its components. Some questions to ask yourself: How long can this filter be used before parts need replacement? Are replacement parts readily available? How much do these parts cost? Is the filter or purifier durable enough to reliably filter water in challenging conditions?

Knowing the lifespan of the parts and the availability of replacements ensures that you're equipped for extended trips and can swiftly address any maintenance needs. "If you're a person who doesn't like to do a lot of maintenance, maybe the [filter] that requires backflushing more frequently or [necessitates] a more involved process to maintain isn't right for you in the long run," Lindsey says.

Maintenance and Cleaning

Speaking of maintenance: Each filter has its own cleaning and care requirements, and some are more user-friendly. Some filters need frequent backflushing, while others need filter replacements after a certain number of uses. When it comes to maintaining your water filter, one REI customer-reviewer has great advice: "The key to longevity is proper cleaning and maintenance. Always store the [filtration] system cleaned and dried. Also, be sure to run some water through the system and backflush the filter before heading out so that you're not stuck at your first watering site trying to make sure your filter is still working!"

Prefiltering

Prefiltering water involves an initial stage where larger particles and sediment are removed to prevent clogging and enhance the efficiency of the main filtration process. "Prefiltering will help extend the filter's life before it has to be backflushed or replaced entirely," says Lindsey. People can use methods and techniques to do this manually, but some devices have prefilters built in. "It's important to either figure out a way to prefilter your water or be ready to back flush or replace that filter more frequently," she says.

Always Test at Home First

We can't stress this point enough: Testing and practicing with your water filter before heading outdoors is crucial to ensure its proper functionality and preparedness. It familiarizes you with its operation, allowing you to troubleshoot any issues and streamline usage in the field.

Methodology

We chatted with REI Co-op staffers and read dozens of customer reviews to pick the best water filters in each category. These selections represent their firsthand experiences and favorite picks.

Related articles:

Hydration Basics

How to Choose the Right Water Filter for Backpacking

How to Treat Water in the Backcountry

Authors

Photo of Ebony Roberts

Ebony Roberts

Ebony Roberts is a freelance writer and editor covering the outdoors, travel and the environment. As a gear reviewer, she’s hiked, camped, paddled and more to find the best stuff to help people get outside.