For 10 years, we've rigorously tested 65+ of the best backpacking water filters. Our updated review compares 20 of the top products available that we bought and tested. Our team of thirsty backcountry testers put these devices and treatments through a battery of side by side tests and comparisons across wide-ranging terrain. To push them to their limits, we used them on the worst waters we could find, including contaminated waterways and stagnant pools. We filtered hundreds of gallons of water to bring you our best recommendations for the right set-up to keep you happy and healthy on every adventure.
The Best Backpacking Water Filters
Best Overall for Group Use
The Platypus GravityWorks is an awesome backpacking filter and maintains its podium for its fast and simple design. This gravity system features two super durable bags marked as "clean" and "dirty" to keep microbes out of your water. The transparent "clean" bag ensures that water is, in fact, clean, and can be hung to double as a solar shower or hand washing station. This ultra-versatile system is suited for all sizes of groups, from the solo hiker to a large basecamp.
Unfortunately, this system does not treat viruses and the bags can be hard to close in cold weather. Also, the hanging attachments look a little less durable than other options, with some online users reporting that they can rip out (though we didn't see any issues of the like). If you decide to travel internationally, you can swap out the filter for an in-line option that does treat viruses like the Aquamira Frontier Max or use chemical treatment in conjunction with it.
Read Review: Platypus GravityWorks
Best Overall for Personal Use
The Sawyer Squeeze is one of the most time-tested on-the-go filtration systems. This lightweight filter is perfect for personal use, providing great functionality on multi-day excursions and daily adventures into the backcountry. Of the multiple Sawyer Squeeze systems, this one offers the fastest flow rate, filtering one liter of water in just 40 seconds. We love how packable it is and the great level of longevity the filtration unit offers. It can be used as a squeeze-filtration system, an in-line filter with your hydration bladder, on top of a water bottle, or even as a straw to drink straight from the source. Versatility.
While this is one of our favorites, our biggest caveat lies with the included squeeze bags. After filtering several liters, each of the squeeze bags that we tested failed at the seam. Luckily the filtration unit is compatible with many other products and fits a plastic water bottle, too. While these alternatives proved to be our preference, we'd say that Sawyer should thus work on making some stronger bags. In addition, because there are many parts, it's important to keep them together in the mesh bag and to avoid use in water with lots of sediment. Still, it's our favorite system for personal use in a crowded market.
Read Review: Sawyer Squeeze
Best Bang for the Buck
Katadyn Gravity Camp 6L
We love the Katadyn GravityWorks for its super-easy-to-set-up design and fast flow rate. It treats vast quantities of water in minutes, making it an excellent option for a large group or solo us. The filling is easy as the water bag has a large opening and can easily be squished down. This system does need to be suspended from a high location and it'll do the rest while you do chores around camp. It's compatible with most hydration bladder systems and can double as a handwash station or shower.
Unlike other gravity filters in this review, it does not come with an additional storage bag for clean water. Because of the placement of the filter in the bag, it doesn't work well if there are no branches to hang it from. It clogged quickly when filtering water from the Colorado River after a heavy rainstorm.
Read Review: Katadyn Gravity Camp 6L
Best for International Travel
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 the system, and simply drink. More importantly, this water purifier removes all of the most disgusting water contaminants that you would find in countries all around the world. This includes viruses, protozoa, heavy metals, plastics, and more. The bottle seems pretty durable and provides a wonderful flow of water. It's also more discrete to use when traveling abroad as compared to a gravity filter or a pump.
In comparison to the Grayl Ultralight system, this bottle is much easier to push down, especially with the handgrips along the side. That said, it does take a bit of muscle to push and to separate the two containers from one another. While we appreciate the use of this system, it's also definitely not our first choice for lightweight travel. While many users do use it as a bottle for backpacking, it's heavy and bulky design seems like a bit much. Aside from that, it's one of our favorites and a top scorer in this review, and ideal for international travel.
Read Review: Grayl Geopress
Best for Best Chemical Treatment
Aquamira Water Treatment Drops
If you've got time to spare the Aquamira Water Treatment Drops is a lightweight and inexpensive travel system that is used by many thru-hikers. Treatment is simple: activate the substances, then drop it into your water and wait. Of all the chemical treatment systems, it kills the most stuff, including finicky cryptosporidium cysts. When doubled with a filtration system, it can easily be used anywhere in the world.
Unfortunately, chemical treatment doesn't filter out particulates, so we'd recommend carrying a pre-filter or a handkerchief to do that work. While it's advertised that treatment time is just 15 minutes, which will kill most stuff, you have to wait much longer (four hours!) to get rid of hard-shelled cryptosporidium cysts, a common protozoan in North America. Also, this will leave a slight taste in the water.
Read Review: Aquamira Water Treatment Drops
Best for Fast and Light Missions
Are you going out for a long day in the hills? The Katadyn BeFree is a personal soft hand bottle that fits a high flow filter with a short length inside. Scoop water on-the-go and drink straight from it. It'll filter as you drink, fueled by a soft squeeze and your sucking force. The soft bottle top is adaptable to other narrow bottle tops, making it reusable if it happens to spring a leak. Because the filter is short and the bottle is collapsible, you can roll it up to the size of your palm and stow.
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 five testing periods. So it's not durable. However, since it 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.
Read Review: Katadyn BeFree
The Most Reliable Hand Pump
MSR Guardian Purifier
As the luxury model of all hand pumps, the MSR Guardian Purifier offers amazing performance and construction. This purifier doesn't just get rid of bacteria and protozoa but also viruses, making it perfect to use all around the world. Pumping is super easy and fast. It is best for personal use or with a small group of up to four people. Its auto-backflush system keeps this filter from being clogged…even in turbid water.
The biggest downfall of this purification system is its heavyweight and bulky design. If you're primarily backpacking in North America, we'd opt for a lighter and less expensive product. However, if international travel where viruses are problematic is your primary use, it's an okay option for shorter backpacking trips where weight isn't a big concern.
Read Review: MSR Guardian Purifier
Best for Large Groups or Basecamps
MSR AutoFlow XL
The MSR Autoflow XL is designed for large group use and basecamps. Its large capacity can hold up to 10L of water, with an adaptable design fitting many different storage vessels. This is our favorite for group use simply because it requires very little set-up and can be left unattended while filtering large quantities of water. it can also double as a hand-wash 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. As long as users know and accept this fact, it's a fantastic large group option. In addition, a stable tree or hanging anchor point must be able to hold 22lbs of weight, if you're planning on using it for its whole capacity.
Read Review: MSR Autoflow XL
Why You Should Trust Us
Jessica Haist and Amber King are both senior OutdoorGearLab Editors that love to explore in the backcountry. Both are from Toronto, Ontario and both work in outdoor education. As educators, they spend lots of time in the woods, backpacking along trails and exploring remote locations. Jessica lives in California and in her free time, you can find her playing at the local granite crags, sucking up rays of the sun, or riding trails on her mountain bike. Amber lives in Colorado and is an avid ultrarunner who likes to fast pack. She runs/hikes long distances with her camping gear and sleeps in places in between. Just last summer she fastpacked the Hornstrandir Nature Reserve in Iceland, carrying only 10 lbs of gear for four days while filtering water along the way.
In our testing, we've run and walked hundreds of remote trail miles, glugging gallons of water filtered and purified from some questionable sources. In our testing, we comparatively test each product through an unbiased lens. We compare the anatomy of each system, dissect the pros and cons, and evaluate whether or not a system is reliable enough to place our lives on it. Our recommendations come from experience in the field and home-based experiments that comparatively test the performance of each product.
Analysis and Test Results
A great backpacking water filter or treatment system will keep you healthy while embarking on missions that lead you far into remote areas. While you're just traveling abroad or going deep into the woods, this piece of gear is a must-have for any seasoned backpacker. It'll protect you from dangerous critters like Giardia and Crypotsporidium found in contaminated water sources in North America. Waterborne viruses are more problematic internationally and a good purification system will keep you protected from infection. In our testing, we look at six different metrics that are the most important to consider. This comparative review article outlines key recommendations and will hopefully lead you to the best system that will support your ambitions.
Price to performance ratios is a super important consideration. Our best buy winners highlight the best-valued products. The Katadyn Gravity Filter is a favorite choice for base camps or processing large quantities of water for the solo or group travelers. While there are several well-priced options, it's important to note that the drops and tablets definitely offer some of the best value out there. They offer the lowest price with the most benefits. For example; the Aquamira Chlorine Dioxide Water Treatment is also our Top Pick for Chemical Treatment and comes at more than half the cost of most filtration systems, with a lighter carry weight, and a higher level of reliability. Other products like the Lifestraw Straw are also lower priced and provide options for on-the-go water filtration that we appreciate and love.
When considering this metric, we specifically look at what the treatment system can get rid of and the overall taste or odor of the water. We went to shallow puddles, smelly swamps, and pristine streams to see what each could do. Those that remove everything including heavy metals and pesticides triumphed in this category.
Water filters and purifiers are a little different from one another. Purifiers use different types of technology to remove viruses in addition to protists, bacteria, and other water-borne pathogens. Filters typically don't have a pore size that can do this. Another category is 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
Water purifiers are what you need if you're traveling abroad or treading in terribly polluted areas. Water purifiers don't only 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 that can do just that. It can expunge smells from water, but it, unfortunately, cannot remove heavy metals like arsenic and cadmium, or chemicals. On the market, there are just a few that can do this.
Our favorite, and a Top Pick for International travel, is the Grayl Geopress. This is a water bottle purification system that uses push technology to scrub water of everything that might contaminate it. We tried this 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 is acidic. After using the purifier, it took all these metals out, and neutralized the pH of the water! AMAZING! We drank it shortly after, not noting 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.
The Aquamira Frontier Max is a unique in-line purification system. It can be attached to a hydration bladder hose, gravity filter, or used on its own to provide water purification. It also has the ability to remove all the substances that you can think of. Of all these, our favorite is the Grayl Geopress for its unmatched convenience and great water quality.
UV light purifiers also effectively eliminate water pathogens. Imagine sitting on a beach in Mexico with a tequila-infused beverage with ice. Unsuspectingly, you get sick. Why? Ice is typically a huge source of sickness for travelers. The SteriPEN Ultra, a UV purifier can be put into the glass and swirled around to destroy pathogens that could cause an infection. Unfortunately, UV light purifiers won't remove particulates, smells, or metals and don't score as high as other purification models.
Water treatments like the Aquamira Chlorine Dioxide Water Treatment, our favorite chemical treatment, can kill most microorganisms but sadly adds a gross taste to the water. In addition, they can't filter out particulates. The Aquamira drops are the best because they kill all organisms (with enough time) while the Potable Aqua Iodine Tablets and MSR Aquatabs can only destroy viruses, bacteria, and some protozoans, but not Cryptosporidium. The active ingredients in these treatments, however, cannot get rid of Cryptosporidium as the drops do. Also, they have the best "chemical" taste of all three options.
Backpacking water filters (not purifiers) can remove particulates, bacteria, protozoans (giardia & cryptosporidium) but can not 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 and Lifestraw Universal can 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, and a great option if you're worried about lead in the water source.
Filters that utilize a 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's essential to plan for water sources that might be saturated entirely with silty sediment (called highly turbid). For example; the Colorado River that 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. Most fail because they clog with residue, except some like the Katadyn Gravity Filter. The only system that held up in these conditions is the MSR 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. Decant the top water layer off 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, just 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 reliable 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. 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 of time. 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, and grave discomfort.Gravity Filters
Of this group, the Katadyn system seems to be one of the best constructed. The bag, unlike the Platypus and both the MSR systems, seems to be far more resistant to punctures and has a lot less going on. The Platypus is made of a strong plastic composite that could come apart at the seams, while the MSR is made of a more rubberized plastic compound. Of all these systems, they all seem very durable and reliable, with the Katadyn being the best.
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 do 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 to retain optimal flow.
Of the three, the Katadyn is the only one that can be used after it's been frozen. Given the filter's internal glass fiber construction, the filaments aren't destroyed when frozen. While it can't filter water when frozen, it is still usable after thawing out! If you're seeking a gravity filter that'll do for a winter camping trip, this is it. That said, it's not freeze-proof! That'd be an amazing innovation.Hand Pumps
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. The Hiker Pro works well too, but many online users report it getting clogged and breaking when clogged and under pressure. This didn't happen during our months-long testing period, though. If you're considering this filter, it's not a bad idea to backflush and clean it on a regular basis to avoid this potential issue.
We are super impressed with the Sawyer Squeeze, lasting up to 10,000 gallons and pretty well built-in nature. 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 option 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 hand 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. To clean, simply swish it in clean water. You don't need to carry any extra parts and clogging does not happen often.
The Sawyer Squeeze and Lifestraw Personal Water Filter are two options that we really 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 so you don't have to get your face into water sources. Both the Squeeze Mini and Micro are fine options for on-the-go carry, but require you to still carry a syringe and straw adaptor.UV Light
This is one of the most unreliable systems simply because it needs a power source. The battery life is supposed to last 50 liters, but we've seen it short out faster than that. The SteriPEN Ultra is a cool idea, but ultimately not one we'd trust on long backpacking trips.
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-time trials and averaged them to determine an average time to filter one liter. The fastest times did best in this metric.
The most immediate backpacking water filter systems are the straw filters that you can drink through immediately from a water 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. It can filter a liter of water in just 40 seconds when in squeeze mode. The Mini, the smallest of the group, takes 2 minutes to filter a liter of water, with the Micro somewhere in between. If you like the Squeeze products and want one with an awesome flow rate, the Sawyer Squeeze is the way to go.Pump Filters
Most backpacking water filter pumps are pretty quick to use unless they get clogged up. The Guardian is the fastest we've tested, filtering a liter in 37 seconds. The Katadyn Hiker Pro by comparison filters a liter in just 53 seconds. Most pump filtration systems can filter one liter in just under a minute.Gravity Filters
Comparable in the rate of flow, 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 effective for small to large groups. All of the gravity filters are super close in treatment time. The Platypus Gravity System is the fastest, filtering one liter in 52 seconds. The Katadyn Gravity Camp filters one liter in 64 seconds. The MSR Base Camp is close behind at 69 seconds. Lastly, the MSR AutoFlow XL took just around 2 minutes, making it the slowest gravity filter 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 to be filled often isn't a big deal.
Weight and Packability
Weight and packability are important. 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 regular packs. The lighter and easier to pack and store, the better the score.
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 both of these results in a chemical taste in the water (for most people). The Aquamira Treatment Drops can't be parsed out like the tablets, but some people prefer them because they don't taste as bad as the tablet options out there.
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 Platypus Gravityworks, is the lightest and most packable.
Ease of Setup
We measured ease of setup based on how intuitive each backpacking water filter system is and how many steps each one requires to set up. We also consider how easy it is to access different water sources.
The easiest set-ups are the ones that require little thought and easy access. No parts or steps to follow. The Lifestraw Personal Filter is basically the best for this. This filter, unlike other more complex on-the-go systems, requires you to find a puddle or accessible water source and simply drink!
Tablets come next. 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, then wait different periods of time depending on what 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, in particular, is a favorite because it's tiny 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. All pump filters are good for reaching water over steep banks when water access can be an issue.
Gravity filters require more effort to set up because you need a place to elevate them. In some cases, you can put it on a rock on a slope and that'll do. In other scenarios, you need to hang it. They typically earn a lower score in this category. Reservoirs that are very flexible with large openings. like those found in the Katadyn Gravity Filter, can get water from most water sources. However, because you have to scoop up water, a trickle or deeper pool needs to be sufficient 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 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 not store.
Gravity backpack water filters are by far the best systems when it comes to ease of filtration. As soon as it's set up, the process is completely hands-off. 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. The Katadyn Gravity works needs 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 prove to 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 physically pump to move water through the system. This can be harder if the filter becomes clogged, and the output is different for each hand pump filter. Of the hand pumps we tested, the MSR Guardian is the easiest to use. It has a large handle that makes pumping easier while the smaller design in the Katadyn Hiker Pro takes more effort to get used to. While these filters are fast, it can be a tiring process, especially if you have a big group to pump many liters of water for. As a result, these are recommended for solo or small group use.
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 that gives you very little water for each suckle. We also love the Lifestraw Adaptor Kit that allows you to turn 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 filters through that. Just make sure you don't drink from that vessel on the trail, or you might suffer the effects.
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 when water sources abound. Either that or you can fill up a "dirty bladder" and carry it around with you, drinking on the go.
There are a lot of different backpacking water filter options out there. Ultimately, you need to figure out what you need for weight, packability, and water quality. Before you go anywhere, be sure to research the water sources and what kinds of pathogens you may contact. It's also not a bad idea to carry a chemical treatment as a backup, especially on long thru-hiker. Cheers to clean water and many adventures ahead deep into the backcountry.
— Amber King and Jessica Haist