Best Backpacking Water Filter
|Price||$103.93 at Amazon|
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|$14.95 at REI|
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|Pros||Fast, easy, hands-free filtration, large volume, storage||Lightweight, adaptable, easy to use, lifetime guarantee||Lightweight, inexpensive, kills all pathogens (including crypto), reliable||Easy to use, fast flow rate, collapsible, lightweight||Competitive flow rate, lightweight and packable, easy to use|
|Cons||A little expensive, can't gather from shallow sources, clogs with heavy sediment||Not great for group use, better if you replace the bags||Takes a long time to kill crypto, slight taste to the water, chemical treatment||Lacks durability and reliability||No separate bag for water storage, shorter filter life|
|Bottom Line||A fast and easy to use gravity filter perfect for small groups||Simple filtration that is lightweight and reliable for individual use||These drops are a reliable and lightweight option to carry all over the world||Our favorite lightweight on-the-go filtration system||Let gravity do the work by selecting this efficient and intuitive filter for your next backcountry base camp|
|Rating Categories||Platypus GravityWorks||Sawyer Squeeze||Aquamira Treatment...||Katadyn BeFree||Katadyn BeFree Grav...|
|Water Quality (20%)|
|Durability & Maintenance (20%)|
|Treatment Time (15%)|
|Weight & Packability (15%)|
|Ease Of Set Up (15%)|
|Ease Of Filtration (15%)|
|Specs||Platypus GravityWorks||Sawyer Squeeze||Aquamira Treatment...||Katadyn BeFree||Katadyn BeFree Grav...|
|Type of filter/purifier||Gravity filter||Squeeze, in-line, on-the-go||Chemical treatment||Squeeze & on-the-go||Gravity filter|
|Measured weight (entire kit, oz)||11.5 oz||5.7 oz||3.0 oz||2.1 oz||9.28 oz.|
|Number of liters (L)/gallons (gal) per lifetime||1,500 L/396 gal||378,541 L/100,000 gal||114 L/30 gal per package||1000 L/264 gal||1,000 L|
|Filter media or active ingredient||Hollow fiber||Hollow Fiber||Chlorine Dioxide||Hollow Fiber||Hollow-fiber|
|Effective against bacteria?||Yes||Yes||Yes||Yes||Yes|
|Effective against protozoa? (Cryptosporidium, Giardia)||Yes||Yes||Yes||Yes||Yes|
|Effective against viruses?||No||No||Yes||No||No|
|Effective against chemicals?||No||No||No||No||No|
|Effective against heavy metals?||No||No||No||No||No|
|Removes Particulates (sediment, microplastics)?||Yes||Yes||No||Yes||Yes|
|Filter pore size||0.2 microns||0.1 micron||N/A||0.1 micron||0.1 micron|
|Advertised flow rate||1.75L/min||1.7L/min||N/A||2.11 L per min||2L/min|
|Dimensions||9.4 x 3 in||11 x 6||N/A||9.05 in x 2.73 in||15 x 9 in|
|Storage capacity (L)||8 L||2 L||0||0.6 L||6 L|
Best Overall for Small Group Use
The Platypus GravityWorks is our favorite gravity-fed backpacking water filter. This model is fast, portable, and easy to use. Setting it up is effortless, and its 4-liter potable water capacity is perfect for personal or a small group use. The kit is equipped with two durable 4-liter bags (one "clean", one "dirty") and a high-flow filter that is compatible with water bottles and hydration bladders. The bags also can convert to a solar shower or hand washing station to make your base camp complete. We love that we can simply hang it up with dirty water, walk away, and enjoy effortlessly (no pumping, no squeezing, hardly any waiting) filtered water within minutes. For its versatility and ability to make filtering water a breeze, we think its 11.5-ounce weight is worth carrying on most trips.
While there aren't many downsides to this great filter, it is important to know that the system does not treat viruses. We also had minor difficulty closing the zip-top on the bags in cold weather. The hanging attachments don't seem as durable as some other options from our testing, but even after several trips into the backcountry, we never experienced any issues with durability. Also, like any gravity system that uses an in-line filter, the flow rate will slow down when exposed to water containing high amounts of sediment and will need to be removed by flipping the filtration unit upside down. For a durable and easy-to-maintain gravity filter with a high flow rate, this is our favorite to recommend to friends and readers alike.
Read Review: Platypus GravityWorks
Best Overall for Personal Use
The Sawyer Squeeze is a time-tested, on-the-go filtration system. This lightweight option is wonderful for personal use, providing great functionality on multi-day excursions and daily adventures in the backcountry. Of the multiple Sawyer Squeeze systems, this one offers the fastest flow rate, filtering one liter of water in just 40 seconds in our tests. It's also very packable and easily fits into a running vest or pocket. You can use it as a squeeze filter with its accompanying bags or in-line with a hydration bladder. You can even attach it to the top of a compatible water bottle or drink directly from puddles with its complementary straw. Few contenders offer this level of versatility and portability, making it our favorite for personal use.
Unfortunately, over our four years of experience testing the Sawyer Squeeze, we noticed a durability issue with the provided filtration bags. After just three or four trips in the backcountry, these bags need to be replaced. We recommend buying a Platypus Hydration Bladder as a substitute that will outlast the Sawyer bags that are included with the system. We also recommend bringing the syringe for cleaning in order to ensure an efficient flow rate, otherwise, the filter will clog and the flow rate will decrease after just a few filtrations. It also comes with small parts, which are easy to lose. The Sawyer Squeeze is a great lightweight option for day trips and personal use so long as you don't forget all its moving parts.
Read Review: Sawyer Squeeze
Best Bang for Your Buck
Aquamira Water Treatment Drops
If you've got time to wait for your potable water, the Aquamira Water Treatment Drops is a lightweight and inexpensive travel system used by many thru-hikers. Treatment is simple: activate the substances, then drop them into your water and wait. Of all the chemical treatment systems, it kills the most bacteria, including cryptosporidium cysts when given ample time. When doubled with a filtration system, these drops can easily be used anywhere in the world. Plus, these drops are inexpensive and incredibly packable. There is no need to do field maintenance and the drops inherently never clog, which are bonuses that increase their reliability.
Unfortunately, chemical treatment doesn't filter out particulates, so we recommend carrying a pre-filter or a handkerchief to assist with that work. While it's advertised that treatment time is just 15 minutes, you have to wait much longer (four hours is recommended) in order to get rid of hard-shelled cryptosporidium cysts. These drops are our favorite chemical treatment for backcountry water due to their packable design and ease of use. Just make sure you have time to wait for your sterilization. The Aquamira Treatment Drops offer a great value for a couple of trips into the backcountry, but if longer-term value is what you're seeking, the Sawyer Squeeze will last longer, and is meant to filter around 100,000 gallons over the course of its lifetime, though expect a bigger cost upfront.
Read Review: Aquamira Water Treatment Drops
Best Collapsible Bottle Filter
Are you going out for a long day in the hills? The Katadyn BeFree is a personal-sized model with a high flow filter in a collapsible, packable bottle. Scoop water on the go and drink straight from the packable bottle. It will filter as you drink, fueled by a soft squeeze and your guzzling force. The soft bottle top is adaptable to other narrow bottles, making it reusable if your bag happens to spring a leak. In the field, the short filter and collapsible bottle roll up to the size of your palm and are easily packable. If the filter gets clogged, find a stream and simply swish it around. For ultra-distance adventures where you might already be using a soft bottle, this system is simply awesome and can't be beaten for its functionality.
The biggest issue with this product is the durability of the soft bottle. We have had this bottle spring leaks on us pretty consistently over the last several testing periods. However, since the filter itself is adaptable to other bottles, it can be used over and over again. It also only holds 0.6 L of water and can't be used for large storage, so water sources need to be plentiful. Use this system if you're seeking a super lightweight filtration option that boasts a high flow rate and a soft, packable bottle.
Read Review: Katadyn BeFree
Best UV Bottle Purification System
The CrazyCap uses UV light to allegedly sterilize surfaces and water sources from viruses, bacteria, and protozoa. It uses a USB charging cable to charge the bottle cap (that is compatible with some other bottles), so maintenance is easy. Simply press on the top twice to purify the water you've collected in the bottle, and get 0.5 liters in just 60 seconds. The cap-based system makes it versatile, and it can easily be used while hiking, traveling abroad, or around the house.
While this system is a nice idea, we've got to say that it's hard to trust that the UV light is actually working. It almost seems magical and definitely had us wondering if the system even worked. That said, none of our testers got sick after using it during international travel in Central America. Aside from that, this is not a filtration system, so don't expect it to get rid of particulates. It doesn't protect from chemicals, pesticides, or heavy metals. This self-contained UV light water purifier is super convenient and an option we'd recommend when considering international travel or where a clear water source might contain a virus.
Read Review: CrazyCap 17oz
Excellent for Turbid Water
MSR Guardian Purifier
The MSR Guardian stands out for its exceptional ability to remove water-borne viruses and other pathogens, providing pure potable water unlike other hand pumps on the market. The hollow fiber filter has a massive expected lifespan (which presents a great lifetime value) with easy field maintenance. It's built to last, it's tough, and it's strong. We've owned one for over seven years and it's performed well during international travel or hiking in the backcountry. Its flow rate is exceptional for a pump filter (about 37 seconds for one liter), while the backflush system makes it functional even in the sludgiest of stagnant or turbid water holes. The filter is resilient to freezing, making it an option to consider for trips in colder climates. It's also the only system that performed remarkably well in turbid water due to its built-in backflushing system. If you encounter water muddied with sediment, this is the filter for the job.
While this purification system is quite incredible, it's not for everybody. The initial price tag is immense, and quite frankly, most people aren't willing to invest. If you're looking for a pump filter that will suffice in North America, you probably don't need this Cadillac of hand pumps; a normal hand pump will do. This model is rather large, which will add weight and require more space in your pack. If you need a purifier for international travel or one that offers a backflush system for turbid water, this is one provides reliability that's worth the initial investment for those that are willing to shell out the cash upfront.
Read Review: MSR Guardian Purifier
Large Capacity for Groups or Basecamps
MSR AutoFlow XL
The MSR Autoflow XL is a gravity backpacking water filter designed for large group use and basecamps. Its large capacity can hold up to 10L of water, with an adaptable design fitting various storage vessels. This is our favorite for group use because it requires minimal setup and can be left unattended while filtering large quantities of water. It also doubles as a handwash station or even a shower during the warmer seasons.
While we do love this system, it offers the slowest flow of any gravity filter tested. The filter needs consistent backflushes, especially when dealing with turbid water. If you need to utilize its entire capacity, site selection can be limited by the availability of strong anchors to hang it from. If you require a gravity filter that will filter large quantities of water with minimal effort, this is a good choice.
Read Review: MSR Autoflow XL
Top Value Hand Pump
The Katadyn Hiker is one of the top-selling and most reliable pump filters on the market today. The pump-action system collects water while you actively pump the water through the device and into your water bottle. It works best with a wide-mouthed container (e.g., a wide-mouth Nalgene bottle) and also comes with an attachment compatible with hydration bladders so you can fill up your hydration bladder with ease. This mid-range pump is fast, smooth, and easy to use. It's one of the most consistent in its performance, offered at a great price.
Unfortunately, this pump is difficult to clean when it gets completely clogged. The filter also absorbs water and cannot withstand a freeze thereby limiting its use in colder climates. If you're looking for an affordable hand pump filter that works efficiently in most environments, the Katadyn Hiker is a great option to consider.
Read Review: Katadyn Hiker
Best Bottle Press Purifier
The Grayl Geopress quickly turned into one of our most used and favorite purification systems. In comparison to the rest, it supersedes most systems for a variety of reasons. It's easy to collect water, push it through, and drink right away. More importantly, it removes the most disgusting water contaminants that you would find. Not only including viruses, but it's said to remove heavy metals, plastics, pesticides, and more. When we tested this in a heavy metal polluted river in Ouray, CO, our water came out clear. We believe that no other system could purify this well, either leaving some detectable smell or discoloration behind. The bottle is very incredibly durable and met our needs while traveling. Save yourself from buying tons of disposable water bottles during travel and get the Grayl Geopress instead.
Compared to the Grayl Ultralight system, this bottle is much easier to push down in order to force the water through the filter, especially with the handgrips along the side. While we appreciate the use of this system, it's also not our first choice for lightweight travel in the backcountry because of its bulky, heavy design. The cartridge life is minimal, and refills are pretty expensive. Based on these cons and our comparisons, we find this product provides relatively low value for the price. But for traveling abroad, it offers peace of mind when collecting water from taps or other polluted sources.
Read Review: Grayl Geopress
Why You Should Trust Us
Jessica Haist, Amber King, and Trish Matheny are seasoned gear testers (over 25 years of collective experience) who love to explore in the backcountry. Both Jessica and Amber work in outdoor education. As educators, they spend lots of time in the woods, backpacking along trails, and exploring remote locations. You can find Jessica playing at the local granite crags, sucking up rays of the sun, or riding trails on her mountain bike. Amber is an avid ultrarunner and rock climber. She currently runs and owns a non-profit that takes kids into the backcountry daily. Trish is most likely to be out of cell reception while exploring the mountains surrounding her home in Crowley Lake, California. She splits her time between running ultra distances and climbing the endless Sierra granite. Our testing team uses these filters throughout all seasons of the year, with over a decade of cumulative experience testing these filters and purifiers.
To test each product, we take to the trails. We run, hike, and bike hundreds of remote trail miles with filters in tow, guzzling gallons of water filtered and purified from trailside sources. Using a systematic test plan, we assess each system's anatomy, dissect the pros and cons, and evaluate whether a system is reliable enough to earn our favor. Each product sees hands-on and in-field experience. We also perform rigorous indoor tests to determine minute differences between products. Specifically making sludgy water samples using fertilizers, soils, and other particulates to truly test how each filter and purifier performs. Our recommendations come from experience in the field and home-based experiments that comparatively test each product's performance.
Analysis and Test Results
With a focus on backcountry water filters, we chose a wide variety of options that you'll encounter on the market. While it might be difficult to assess different categories of water treatment products, for example; chemical treatment versus a hand pump, the metrics used to evaluate each filter offer helpful insight to which products excel in one area or another. Using this information, we hope to help you find exactly what you are looking for.
A great purifier or filter lasts a long time and doesn't cost an arm and a leg to maintain. While the original ticket price on some items might seem low, the expenses of replacement parts might add up, running up a larger bill over the life of the filter. The Sawyer Squeeze systems and CrazyCap bottle offer impressive value because they provide more filtered or purified liters before requiring replacement than other models that we tested.
The Katadyn Hiker Microfilter is a pump filter with great reliability and longevity for the single hiker at an affordable price, compared to pump filters that tend to cost much more. While purification tablets and liquids like the Potable Aqua Drinking Water Germicidal Tablets and Aquamira Water Treatment Drops have a low upfront cost, they offer a lesser value per liter over time as they need to be replaced every 30 liters or so. When considering the price, consider how you'd like to pay for your system—either with minimal, repetitive costs or a larger sum less frequently.
When considering this metric, we specifically look at what the backpacking water filters can remove as well as the overall taste and odor of the water. We went to shallow puddles, smelly swamps, and pristine streams to see what each filter could do. Those that remove everything, including heavy metals and pesticides, triumphed in this category.
Backpacking water filters and purifiers use different types of technology to remove viruses in addition to protozoa, bacteria, and other water-borne pathogens. Filters typically don't have a pore size that can remove viruses. Other categories are chemical tablets and UV light systems. Below, we outline the different types of purifiers and filters out there and what they are capable of eliminating.
Water purifiers are what you need if you're traveling abroad or treading in terribly polluted areas. Water purifiers remove particulates, protists, and bacteria, but can also rid the water of viruses. For example, the MSR Guardian is a tried and tested hand pump purifier that can do just that. It can expunge smells from water and remove viruses, but it can't remove heavy metals or chemicals from water sources. That said, if you're traveling internationally, it's a great companion to filter water from the sink or from a local stream.
The Grayl Geopress stands out above the rest because this water bottle purification system uses push technology to scrub water of contaminants. We tried this system on a particularly contaminated stream in Ouray, Colorado, that runs yellow from pollutants like lead, arsenic, chromium, and iron oxides. The water smells acidic, and it is acidic. After using the purifier, it removed all these metals and neutralized the pH of the water, which amazed our testers. We drank it shortly after, not experiencing any weird tastes or side effects. The Grayl Ultralight provides the same level of water quality as well but is much more of a pain to use. This is a filter we'd trust to produce safe potable water from any source, whether you're traveling to Africa, Thailand, India, or anywhere abroad. We'd also take the MSR Guardian with us, but we'd be more careful about our water source. That said, the MSR Guardian has a much longer lifespan and can process more water in bulk, where the Grayl can only process 750mL at a time.
The Aquamira Frontier Max is a unique in-line purification system that removes viruses and other contaminants. It can be attached to a hydration bladder hose, gravity filter, or used on its own to provide water purification. So instead of filtering your water and drinking it, you suck the water through the filter. It's a good option if you don't like to pump or press water. The only issue is it takes quite a bit of sucking power.
UV light purifiers also effectively eliminate water pathogens. UV light like the SteriPEN Ultra, a UV purifier can be put into a glass of liquid and swirled around to destroy pathogens that could cause an infection. We tested two UV purifiers in this review, the SteriPen and CrazyCap. Both are easy to use. The SteriPen is a long structure that you swish around in your water while the CrazyCap is a lid with a UV light built into the bottom, so purification happens inside the bottle. Both offer the same water quality level. Unfortunately, UV light purifiers won't remove particulates, smells, or metals and for this reason, don't score as high as other purification models.
Chemical treatments are effective, though they all impart an off-flavor to the water and do not filter out particulates. The Aquamira Water Treatment Drops is our favorite chemical treatment. The Aquamira drops are the best because they kill all organisms (with enough time) while the Potable Aqua Iodine Tablets and MSR Aquatabs can destroy viruses, bacteria, and some protozoans, but not Cryptosporidium. The active ingredients in these treatments cannot get rid of Cryptosporidium as the drops do. The drops have the least "chemical" taste of all three options, which scored points among our testers. Try filtering the water through a buff or handkerchief ahead of treating the water to reduce sediment if necessary.
Water Filtration Units
A backpacking water filter (not purifiers) can remove particulates, bacteria, protozoans (Giardia & Cryptosporidium) but cannot remove viruses. The best filtration systems can remove chemicals, heavy metals, and odors using activated carbon embedded in the core of the media.
Of the backpacking water filters, the Katadyn Hiker Pro, Katadyn Hiker Microfilter, MSR Miniworks EX, and Lifestraw Universal offer protection from both microorganisms and chemicals like pesticides to improve the taste of the water. The LifeStraw Flex can remove lead, which is a unique property. This is an excellent option if you are concerned about lead in your water sources.
Filters that utilize hollow fiber filtration media, like the Platypus GravityWorks and the MSR Autoflow XL, are plentiful in this review. If it doesn't have a carbon core, don't expect it to improve the taste of water or remove chemicals. These two gravity filters, for example, cannot remove these contaminants.
A Note on Water Turbidity
It may be useful to plan for water sources that might be saturated entirely with silty sediment (called highly turbid). For example, the Colorado River, which has carved out popular backpacking locations like the Grand Canyon, is one of the most turbid rivers in the world. If you live close to it, you've seen it transform from a clear greenish color to what looks like chocolate milk shortly after rainfall.
Most backpacking water filters and purification systems cannot deal with the amount of sediment and silt in water sources like this. The only system that held up in these conditions is the MSR Guardian Purification System, another reason it's one of our favorites. It utilizes an auto backflush that cleans the filter with every pump.
If you plan on traveling to areas with high turbidity, bring a gallon ziplock bag or a bag designated for settling water. Scoop up the silty water and let it settle for a few minutes. Clearwater will remain in the upper column, with sediment falling to the bottom. Gradually pour the upper layers of water into your filtration device, or filter from the top of the bag. This is an easy and cheap "pre-filtration" technique for these areas. Some gravity systems have a "sediment collecter" in the bottom, like the MSR Autoflow XL.
Durability and Maintenance
Reliable backpacking water filters are durable in construction. You don't want to be without a filter simply because it gets dropped. You also don't want to spend hours maintaining it. 21st-century products are available that offer high quality and reliability with minimal durability.
The most durable and reliable products are chemical treatments. Each comes in either jars or prepacked packets that can go into a plastic bag. They have no moving parts, don't require maintenance, and don't expire. If you want 100% reliability, this is it. The Aquamira Treatment Drops is a favorite of ours. We would strongly recommend carrying these as a backup system, especially when traveling into the backcountry for extended periods. There are too many situations where filters can clog, parts might be lost, or things may not work. Carrying these treatment drops can mean the difference between life, death, or grave discomfort.Gravity Filters
All of these systems have filters that require frequent maintenance and care, depending on how much sediment is in the water you are filtering. Both the Platypus and MSR systems use the same hollow fiber technology. It's important to know that regular back flushes are required, which is simply flipping the filter upside down and allowing water to run through it. Alternatively, the Katadyn requires a rinse and has more moving parts, which is hard to clean with water that isn't clear of sediment in the first place. All systems are pretty durable and easy to use; just be sure that you're amenable to their maintenance in order to maximize the flow.
These models are pretty durable in general until they get clogged. The MSR Guardian is the most durable and maintenance-free backpacking water purification system that we'd trust anywhere. It auto cleans, even in turbid water, offering the best reliability in terms of hand pumps. It can also be frozen, unlike any other hand pump system. The MSR MiniWorks EX is another reliable hand pump. It uses a ceramic-carbon core that can easily be serviced in the field. Unfortunately, it does require a lot of maintenance to keep it working well (lots of scrubbing), but it can be fixed in the field.
The Katadyn Hiker Pro and Katadyn Hiker models are extremely consistent in performance. Both use a glass fiber filter that, if you allow it to become completely clogged, needs to be replaced. Both can be serviced infield, but you must be careful not to keep pumping if performance decreases. Between the two, the Hiker Pro is better by a hair. It's more durable and performs a bit better. For the minimal improvement, though, we tend to recommend the Hiker. These pump filters require less maintenance than the MSR MiniWorks EX.
The MSR Hyperflow is the fastest flowing pump filter tested, but also requires the most service. If the filter is clogged, it can only be backflushed and in order to do so, requires completely disassembling the system. It requires regular backflushing (every 8L in clear water, more in turbid water), and is a bit of pain. It's a durable unit but requires quite a bit of care.
We are super impressed with the Sawyer Squeeze, lasting up to 100,000 gallons with a built-in design. Sawyer offers three systems, the regular Squeeze, Mini, and Micro. With all these systems, the bags breaking when in "squeeze" mode are the most annoying. When squeezed too hard, the bags break at the seams, with the Mini being the most problematic of them all. The regular Sawyer offers a good amount of flow, with less squeeze-force required, breaking fewer bags overall. All of these systems do require you to carry a plastic syringe to backflush after most uses. Overall, the regular Squeeze requires the least maintenance simply because it's a bigger squeeze system than the rest.
Another great squeeze bottle is the Katadyn BeFree 0.6L, our favorite for lightweight missions like trail running. The bottle that it comes with is also prone to leaking. However, we found that it can be attached to other handheld bottle options that are much more durable. Overall, its durability is a drawback, but the filter itself offers some of the best flow and adaptability. Cleaning is easy; just swish it in clean water. You don't need to carry any extra parts, and clogging does not happen often.
Not to be overlooked, the Platypus QuickDraw is a solid choice for a squeeze filtration system. It is the only filter that we tested to offer an integrity check if you suspect your filter is compromised after being dropped or frozen. Simply fill the reservoir with clean water and start by filtering some water through the system, then invert the filter to begin filtering air through the system, if there is a constant stream of bubbles, this indicates a compromised cartridge that needs to be replaced.
The Sawyer Squeeze and Lifestraw Personal Water Filter are two options that we like. If you're seeking the most barebones option that doesn't require you to carry extra items, the Lifestraw is where it's at. It's light, easy to carry, and long enough to provide easy access to water sources. Both the Squeeze Mini and Micro are fine options for on-the-go carry but do require you to carry a syringe and straw adaptor.UV Light
This is one of the most unreliable systems simply because it needs a power source. Battery life can be tough to predict, especially in colder temperatures. The CrazyCap earns a higher score than the SteriPen here because it's completely waterproof. It also requires less time to charge overall. One charge lasted us about 30 liters but only took 1.5 hours to charge completely. After testing it for months, it was consistent. Neither are units we'd completely trust on a long backpacking trip, but both are suitable for travel or purifying municipal water sources regularly.
Backcountry Field Maintenance
While we do outline how to maintain each unit in the backcountry, it is important to point out which options are the easiest to clean and which options add to the filter's overall reliability in the field. This is especially true for those making a big choice about long backpacking trail hikes where the water filter that is chosen will be the only one used for weeks or months on end.
Of all the options tested, the easiest units to clean in the field are those that can simply be backflushed like the Platypus GravityWorks 4L and MSR AutoFlow XL. Some filters, when thoroughly clogged, require a complete replacement, which isn't ideal when you're in a remote space. The easiest for maintenance is by the far the MSR Guardian Purifier that claims no maintenance (and with our experience has been hassle-free) as it backflushes and cleans itself.
In this metric, we consider how quickly you can get water from the source to a filtered state. To test this, we noted if water filtration is instantaneous. If not, we performed three separate time trials and averaged them to determine an average time to filter one liter. The fastest times received the highest scores.
The most immediate backpacking water filter systems are the straw filters that allow you to drink water directly from the source. The Aquamira Frontier Max and Lifestraw Flex are a few of our favorites. Water flow is typically slower but very much based on the construction of the input, filter body, and straw or bite value. For example, the Lifestraw Flex and Aquamira Frontier Max have comparable flow rates, not requiring as much effort as the laborious Lifestraw Personal Straw.
These backpacking water filters use a collapsible bottle or pouch, offering a little water storage. The Sawyer products all demonstrate this adaptability, but our favorite is the Katadyn BeFree for its fast flow bite valve that delivers water quickly. This makes it a favorite among trail runners because water collection takes no time, and treatment is instantaneous.
Of all the Sawyer products, the Sawyer Squeeze offers the best flow rate during our side-by-side tests. It can filter a liter of water in just 40 seconds when in squeeze mode. The Mini, the smallest of the group, took 2 minutes to filter a liter of water, with the Micro somewhere in between. You can also consider the Platypus QuickDraw offering a flow rate of 44 seconds per liter. However, if you like the Squeeze products and want one with an awesome flow rate, the Sawyer Squeeze is the way to go.Pump Filters
We pumped over 40L of water and timed it to see how many strokes each took, and which were the fastest. The hands-down winner in this category is the MSR Hyperflow (27 seconds, 29 strokes per liter). It pumps out hoards of water super quickly. However, this model was also the quickest to slow down, reducing its flow rate significantly as the liters added up. The MSR Guardian Purifier placed second, filtering a liter in 37 seconds and maintaining performance even in the murkiest of water. The other pumps followed as such the Katadyn Hiker Microfilter (42 seconds, 52 strokes), then the Katadyn Hiker Pro (53 seconds per liter), and lastly, the MSR MiniWorks EX (80 seconds, 90 strokes per liter).
The Katadyn products and the MSR Guardian offered the most consistent performance overall, with these working best in Turbid conditions. The MSR Hyperflow and MiniWorks EX needed cleaning almost every 4L in these tests. In our sludge tests, all the pump filters needed to be cleaned out after processing every liter, except the MSR Guardian.Gravity Filters
Comparable in the flow rate, gravity filters are nice because you conveniently don't have to pump or do anything once they are set up. They can process large quantities of water, making them highly useful for small to large groups. All of the gravity filters are super close in treatment time.
The Katadyn BeFree Gravity 6L is the fastest, filtering one liter in 40 seconds. The Platypus Gravity System comes in second place, filtering one liter in 52 seconds. The MSR Base Camp is close behind at 69 seconds. Lastly, the MSR AutoFlow XL took just around 2 minutes per liter, making it the slowest gravity filter that we tested. While gravity filters are inherently rad because there's so little work involved, there are some stark differences in performance. Please note that these flow rates will decrease with murkier or turbid water, and if the filters are not properly maintained. Also, note that if you aren't rushing, the difference in passively waiting one or two minutes for a liter of water often isn't a big deal.
Weight and Packability
Weight and packability are essential. If you're carrying less weight, long hikes can be more enjoyable. To assess this metric, we weigh each system and look at its relative profile. We tested them with hydration vests, backpacking backpacks, and day packs. Generally, products that were lighter and easier to pack scored better than bulkier options.
Of all the treatments out there, chemical treatments are by far the lightest. If you're planning a long thru-hike or huge trail run, they're a great choice. Of the treatments, the MSR Aquatabs and Potable Aqua Drinking Water Germicidal Tablets can simply be put into a little baggy, without requiring you to carry the whole bottle. This helps to eliminate weight. The only downside is that both of these result in a chemical taste in the water (for most people). The Aquamira Treatment Drops can't be parsed out like the tablets, but some prefer them because they don't taste as bad as the tablet options.
The lightest filtration systems out there are on-the-go systems like the collapsable Katadyn BeFree and Lifestraw Personal Filter. The lightest purifying on-the-go filter system is the Aquamira Frontier Max. Of the gravity filters, the Katadyn BeFree Gravity 6L is the lightest and most packable (9.28 oz). If you prefer a hand pump system, the lightest systems are the MSR Hyperflow (10.6 oz) and the Katadyn Hiker Pro (13.2 oz).
Ease of Setup
We assess ease of setup based on how many steps each filter requires to begin filtering water as well as whether or not that setup feels intuitive. We also consider how easy it is to access different water sources.
The easiest setups are the ones that require little thought, few instructions, and easy access. The top models have no parts to carry around or steps to follow. On-the-go systems prove to be the easiest here. The basic Lifestraw is the best for this. Unlike other more complex on-the-go systems, this filter requires you to find a puddle or accessible water source and simply drink.
Purification Tablets are also pretty simple. Those like the MSR Aquatabs and Potable Aqua Drinking Water Germicidal Tablets require you to drop them in the water and wait. The Aquamira Water Treatment Drops are also pretty simple, but with a steeper learning curve. These require you to follow a series of specific steps where you have to mix two solutions and wait for a specified time amount of time. The time frame depends on what contaminates you need to eliminate from the water.
Hand pumps are also relatively easy to set up and offer great access to all sorts of water sources. The Katadyn Hiker Pro, Katadyn Hiker Microfilter, and MSR MiniWorks EX are favorites because the intake can grab water from the smallest nooks and crannies. The MSR Guardian works well for this, but it has a larger particle screen that makes it harder to reach shallow sources. Pump filters excel at reaching water over steep banks, boat sides, or fast rivers when water access can be an issue.
Gravity filters require more effort to set up because you need a place to elevate them. The ideal scenario is to hang the filter from a branch. If that is not available, you may need to get creative in a pinch; a rock could work. Reservoirs that are very flexible with large openings can get water from most water sources. However, because you have to scoop up water, the source needs to have a sufficient pool to collect water. Shallow pools are harder to reach.
Ease of Filtration
In the ease of filtration metric, we look at the amount of effort required physically to get water through the backpacking water filtration system. While we don't score storage capacity, we note how much water each system is designed to store or if another bottle is necessary for storage.
Of all the categories, both the SteriPen Ultra and CrazyCap require the least amount of work. Simply fill up the bottle and turn the light on. The SteriPen requires a little less time to filter a liter in comparison to the CrazyCap. However, we appreciate that the CrazyCap is completely hands-free, and you can keep hiking while it purifies your water.
Gravity backpacking water filters are by far the best systems when it comes to ease of filtration. After set up, the filtration process is hands-free. All gravity filters in our review earn top points, all being easy to filter. These filtration systems can move lots of water quickly, making them a top choice for groups. One difference is the height requirement to filter. Some need full suspension and can't be put on the ground, while the MSR BaseCamp, MSR Autoflow, and Platypus GravityWorks can be laid on a hill or over a rock and still filter water.
Some come with "clean water" vessels like the MSR Basecamp and Platypus GravityWorks while others like the Katadyn and MSR Autoflow have a simple hose running from the bag to a storage vessel of your choice. All adapt nicely with a hydration bladder and can be filtered into a bottle if needed.Hand Pumps
Hand pumps are a little harder to use as you need to pump to move water through the system physically. Hand filters vary by design and efficiency, which is dictated by output per pump. Of the hand pumps we tested, the MSR Hyperflow and MSR Guardian are the easiest to use. Both are highly efficient filters, which translates to less pumping and more water production. The Guardian has a large handle that's easy to grab, similar to the MSR MiniWorks EX. The MSR Hyperflow has a tinier system, but it's still pretty ergonomic. All hand pumps we tested have attachments that fit a Nalgene bottle best. The Katadyn Hiker models both have easy-to-use handles, but they aren't as ergonomic as the MSR products. These also require more pumping to get more water. The MSR MiniWorks EX took the most work per liter of all the hand pump filters.
On-the-go backpacking water filtration systems are typically easy to set up but are propelled by either sucking or squeezing forces. Of the on-the-go systems, the Katadyn BeFree, Sawyer Squeeze, and Aquamira Frontier Max are the easiest to suck through when in straw style. Others are harder, like the Sawyer Mini, which gives you very little water for each suckle. We also love the Lifestraw Adaptor Kit that turns a personal water bottle into a filtration system.
These systems don't offer much when it comes to water storage; however, they are adaptable. For example, Sawyer products come with a storage pouch that you can use to store water. Though, if you don't trust these bags, you can find a hydration bladder, a suitably sized collapsible bottle, or even a regular water bottle that is compatible to use instead. You can also simply carry a "dirty Nalgene bottle" and drink through the on-the-go filter.
The Katadyn BeFree bottles have a few different sizes and are compatible with other soft bottles that offer better durability and flow. But for the most part, they are designed to be carried where water sources are plentiful. You can also fill up a "dirty bladder" and carry it around with you, filtering in rounds and drinking on the go.
A critical gear consideration like a water filter or purifier is one that warrants research and excellent hands-on testing. This is where we come in. We hope that our insights have helped you in your search and to narrow down your options. Happy trails.
— Amber King, Jessica Haist, and Trish Matheny
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