There are hundreds of water filters and no best option for all backpacking or hiking uses. We researched over 50 different models before purchasing the top 17 to help you find the best choice for specific applications. We put each model through our exhaustive testing in both the front and backcountry, filtering and drinking hundreds of gallons of water from the murkiest of puddles in Death Valley to the most pristine of mountain streams in the High Sierra. We tested the products for their reliability and treatment capacity, as well as their speed and ease of use. We evaluated each contender's weight and bulk to help you decide the best option for your activity. From trail running to long expeditions, we'll lay out the best options for every circumstance, as well as the best product of the bunch.
Best Backpacking Water Filters and Treatment of 2018
Backpacking season is right around the corner! If you need to retire that water filter and are on the hunt for a new one, you've come to the right place. In addition to ensuring that our previous award winners, like the Editors' Choice Platypus Gravityworks, are still the cream of the crop, we've added four new contenders. The Aquamira Frontier Max is a new contender that filters viruses, while the expanded Katadyn BeFree 3-Liter now filters 3+ liters and is ideal for group settings. The MSR Trail Base takes the cake and is our Best Buy; while $140, it offers up multiple components and a variety of filter options. Finally, the Lifestraw Flex cinches a Top Pick award for Trail Running award.
Best Overall Model
Year after year the Platypus GravityWorks continues to keep ahead of the growing pack of competition, taking the Editors' Choice Award. It's simple, streamlined, lightweight design is easy to use and we love being able to store and filter a large volume of water. The clean water bag is one of our favorite things about this unit. It allows us to store extra clean water for when we need it around camp. The MSR Trail Base now has a clean water bag as well but only has a 2-liter capacity. Gravity filters are, 9 times out of 10 our favorite type of filter for most purposes and here are several high-functioning gravity filters in this review. We like them all, but the GravityWorks is our favorite.
The MSR AutoFlow Gravity Filter uses the same filter unit and has a large, lightweight bag, but has no clean water storage bag, is a very close second to the GravityWorks. The GravityWorks does not treat for viruses and if you're planning to be traveling in a developing country where viruses may be present in a water source you may want to bring one that does.
Read review: Platypus GravityWorks
Best Bang for the Buck
Another time-tested favorite, the Sawyer Mini is a great product at an outstanding price. It wins our Best Buy Award because it truly is a great value, retailing for $25 and able to treat 100,000 gallons of water in its lifetime. It is also the smallest and lightest product in this review, a great choice for backpacking, weighing 2.5 ounces for the filter and bottle combined. The Mini is best used as one person's water treatment system and not depended upon by a whole group. Gravity filters like the Platypus GravityWorks are a better choice for groups.
The included bottle is only 16 ounces so can't filter a lot of water at once, but it can attach to a disposable soda bottle or spliced into a hydration bladder's hose. We think this makes the well priced Mini a versatile choice. The Katadyn BeFree 3L functions similarly to the Mini but has a bigger capacity and can also be used as a gravity filter. We also like the MSR TrailShot as a personal filter.
Read review: Sawyer Mini
Best Buy for a Combo Filtration Set
MSR Trail Base
MSR just released the new Trail Base this year and we've given it our Best Bang for the Buck award because it is a screaming deal for what you're paying for! You essentially get two filters in one - the small hand pump filter the TrailShot which then converts to a gravity filter with a 2-liter dirty and 2-liter clean bag included. The clean water bag is MSR's Dromlite which retails for $27 alone.
We like that you can have the gravity filter set up when you're in camp and just grab the TrailShot if you're going on day hikes or short overnights. It is a versatile choice for a good value. The Trail Base is definitely a jack-of-all-trades and does not exceed at everything. We found the gravity filter slightly slower and clunkier than the other competitors in that category like the MSR AutoFlow but still a great choice.
Read review: MSR Trail Base
Top Pick for Best Chemical Treatment
Aquamira Water Treatment Drops
When you're in an area without much particulate, but still the chance of contaminants in your water Aquamira Water Treatment Drops are a great, lightweight choice to toss in your backpack. Weighing in at 3 ounces these Drops are one of the lightest weight products in this review. If it's hard to drop the dough to buy a fancy backpacking water filter system this is also a great choice because it retails for $15. The 1-ounce bottles will treat up to 114 liters, which is not as much as most filters in this review (average around 2000 liters) but the price tag is way low, and so is the weight. You can also buy 2-ounce refill bottles for $17.
If you're traveling abroad to a developing country Aquamira Water Treatment Drops also eliminate viruses from your drinking water, although you may want a pre-filter if there is a lot of particulate floating around. There is a 30-minute waiting time while the treatment does its job, but we like that you can adjust to treat different amounts of water. MSR Aquatabs only treat 2 liters at a time.
Read review: Aquamira Water Treatment Drops
Top Pick for International Travel
MSR Guardian Purifier
The MSR Guardian is the highest end product in this review, the Porsche or water purifiers. This luxury water treatment method takes our Top Pick Award for International Travel. If you're heading out on an expedition to a place in a developing country with questionable water sources this will be your constant companion. The Guardian is the only pump filter that eliminates viruses. This is the easiest pump to use and the easiest to maintain of all the products we tested as it is self-cleaning, backflushing with every stroke. Normally we think that pump filters are slow and laborious but not the Guardian! It pumped 1 liter of water in only 42 seconds, 2nd only to the Katadyn Gravity Camp 6L.
The Guardian is not a great choice for backpacking in Canada or the US partly because our water sources here are pretty safe, and partly because it is the heaviest and most expensive product of the bunch. Weighing in at 22 ounces and retailing for $350 the only time we'd recommend the MSR Guardian is expeditions where viruses may be present and you have a lot of water to pump.
Read review: MSR Guardian
Top Pick for Trail Running
The new kid on the block from Lifestraw, the Flex takes our Top Pick Award for trail running and all things in a day. This compact, lightweight unit scoops the award from last years winner the Katadyn BeFree. We've discovered some significant durability issues with that product and hope that the Flex's soft-sided bottle does not have the same. So far we have not had any issues with the bottle springing leaks. This is a great choice to throw in your day pack or vest if you'll be traveling near water sources all day instead of carrying your water with you. We also like that the Flex is a versatile product. You can splice it on to a hydration bladder's hose and screw it on to the top of a small-mouthed disposable bottle as well, giving you more options than theBeFree. That said, the BeFree is half the weight and more compact. If you are obsessed on the lightest bottle and filter combo, the BeFree is still the best choice.
The Lifestraw Flex has a small, 20-ounce bottle that does not hold much water and is difficult to treat large quantities of water with so we would recommend it only for personal use. We've also noticed that small leaks occur between the bottle and filter unit when its squeezed hard.
Read review: Lifestraw Flex
Top Pick for Best Pump Filter
Katadyn Hiker Pro
We took a fresh look at an old favorite, the best selling Katadyn Hiker Pro and realized that it has a great niche that other products in this review do not fill. We took this pump into the desert landscape of Death Valley and it was the best tool to get into small and shallow water sources. All hand pumps would have been able to do this, but this is the lightest, sturdiest and fastest of these models.
It is also the most reasonably priced pump model we tested. For all these reasons we think the Hiker Pro deserves recognition. For any other water source that is not shallow or hard to reach we'd prefer a gravity or squeeze model over a pump.
Read review: Katadyn Hiker Pro
Analysis and Test Results
When evaluating various treatment systems, the most important factors we considered were reliability and effectiveness, because if your system doesn't work, then there is no use in carrying it. Also, different systems treat for different contaminants, and it is helpful to know what your system will be treating for. Three of the criteria we evaluated for are equally important: weight, treatment capacity and ease of use. Weight is important because if you're traveling in the backcountry, you want a compact and lightweight system not letting a heavy and clunky filter weigh you down (or you are likely not to even bring it with you).
We also evaluated how well each system can treat large quantities of water so groups or hikers needing a lot of water at base camp can select an appropriate treatment method. Filters no longer need to be cumbersome and clunky, they are becoming more and more comfortable to operate, and we figured out which are the easiest. Next, we compared how long it takes the system to work before you can drink, (speed) and this was where we noticed a significant difference between methods. Read on for more details and comparisons as well as a few other considerations for selecting the filter that will work best for you.
We have several great value products in this review and two Best Buy award winner. The Sawyer Mini is clearly a great value and so is the Trail Base. However, Aquamira Water Treatment Drops are even less expensive, lighter, and might offer the most bang for the buck if you have relatively particle-free water and don't mind waiting. Of the gravity systems, the Editors' Choice GravityWorks is also one of the better deals.
Reliability and effectiveness are related, but are slightly different; there are a few different sub-headings that fall into this category.
Effectiveness: This measures what the treatment system eliminates.Systems That Treat Viruses
If you plan to travel internationally where water sources have a much higher likelihood of virus contamination, take a system that treats viruses. Here are five systems that handle viruses:
- UV light systems, like the SteriPEN Ultra
- Iodine treatments
- Chlorine Dioxide (tablets or drops) like Aquamira
- MSR Guardian Filter
- Sawyer S2 Foam Filter
- Aquamira Frontier Max
The Guardian was a top scorer in this metric because it treats viruses and is super easy to use and can treat a large volume of water. The new Aquamira Frontier Max also treats viruses and is super lightweight, but we had some difficulty getting water through it with its small pore size.
All the other backpacking water filters remove bacteria, cysts, and protozoa like Cryptosporidium (which some of the chemical treatments do not eliminate); they also remove particulate (which many of the above treatments do not remove). Usually, protection against bacteria, protozoa, and cysts is all you need for hiking in the mountains of U.S. and Canada. Virus protection is considered a need for international travel, especially in developing countries.
Chemical and UV treatments typically remove viruses, bacteria, and some protozoa, but not the sediment you might pick up from a particularly dirty source. So, you won't get sick from your water, but it might taste bad or look icky. Different water treatment methods work on various types of organisms. The main difference in effectiveness in the systems we reviewed is whether or not they eliminate viruses or the hard-shelled (meaning hard to kill) protozoa Cryptosporidium.
Reliability is a measurement of how heavily you can rely on the system you are carrying, or if you are likely to need a backup system. We evaluated the durability of each unit based on the different components, resistance to freezing, how much maintenance is required and how easy or complicated the maintenance required is.
Simple pump systems like the Katadyn Hiker Pro and the MSR MiniWorks EX are reliable. More complicated systems like the UV light purifiers are slightly less reliable because of factors such as batteries or bulbs dying. We found our most reliable methods to be ones where not many things can break or go wrong, so they are easy to depend on. The Platypus Gravityworks, Aquamira Water Treatment Drops, Sawyer Mini, and MSR Guardian all fill this requirement. The least reliable were the SteriPEN models due to reports of malfunctioning, and the somewhat short battery life, which makes us hesitant to bring them on multi-day trips.
The MSR Miniworks, MSR Guardian, and Sawyer Mini last quite a while before needing a replacement filter - they treat 2,000 liters, 10,000, and 100,000 liters respectively. The Sawyer Water Filtration System, according to its specs, can last for a million gallons, which is a lifetime of water treatment. The Katadyn, MSR and Platypus Gravity filters all last for 1,500 liters. All of these are long-lasting, reliable options. The filters with the shortest lives are the Katadyn Hiker Pro and the Aquamira Frontier Max, which treat approximately 750 liters and 454 liters respectively.
Systems that have reported issues of durability are the SteriPEN and the Katadyn BeFree. One pair of hikers said the SteriPEN failed after getting rained on (although the new Ultra is watertight), and other users reported random malfunctions and glitches with the light unit we have struggled with battery issues and uncertainty if it's working ourselves with older models. Since our last review, we quickly destroyed the BeFree's 20 oz soft bottle, separating the soft part from the hard plastic collar. We tested the 3-liter version this time around and promptly put a hole in that as well.
Ease of Use
We measured ease of use based on how intuitive each system is and how many steps each one requires to set up and treat water. We also considered the frequency of maintenance and the complication of the back-flushing process.
We find the gravity filter models the easiest to use overall. Just fill up their reservoirs, attach your vessel and leave it alone. The Platypus GravityWorks has a smooth, one step backflush process that involves inverting the clean bag over the dirty bag with no complicated disassembly and you can walk away during the process. Likewise, the MSR AutoFlow is an incredibly easy to use gravity filter.
The Sawyer Mini is one of the easiest backpacking water filter systems: fill up your bottle and drink through the filter, although frequent backflushing is required to make sure the flow is at maximum capacity. Similar to the Mini are other straw filters like the LifeStraw and the MSR Trailshot, which allow you to drink directly from a stream or creek, or to collect water into a bottle and drink it through the filter later. You can also drink straight from the new Sawyer S2 Foam Filter; however, it is a bit awkward, and we preferred to fill another vessel with water, making it slower but easier to drink!
The MSR Miniworks EX and the Hiker Pro lost points for having complicated maintenance routines. The Miniworks' maintenance is fairly intuitive - simply open up and scrape clean the ceramic filter - but this process, which occurs frequently, can be a pain and seems to be relatively frequent if you're using the filter regularly and for multiple people on a trip. The MSR Guardian has revolutionized pump filter maintenance — by having none. Instead, the Guardian self-cleans with every stroke, expelling the dirty back flushed water out a separate hose — we think this is great and wish that every filter had this feature!
The chemical systems require no maintenance whatsoever and typically involve adding to water and waiting. It doesn't get much simpler than that. The SteriPEN Ultra is very simple to use: you push a button, and the screen smiles at you when it is finished. The primary concern with this purifier is that the batteries need to be monitored and charged frequently.
Thankfully, in the new models, we have tested there is a trend towards ease of use and little to no maintenance.
Depending on how frequently you travel into the backcountry or how many people you need to treat water for, you will likely want to consider how much water can be treated by your chosen water filter system. Once again, different methods have different limitations.
Pump filters allow for a seemingly endless amount of water. You can pump as much or as little as you need. All filter units need replacement, but for the short-term, these allow for clean water for a single person or a group for multiple days on end. All you need are some bicep muscles (or finger muscles with the MSR TrailShot) and time to sit and filter into various vessels.
Chemical treatments are not as cost effective for long-term or substantial capacity use, but are light and easy for personal use. You can spend $15 on drops or tablets, and that leaves you with a limited number of treatable water; for instance, a package of the MSR AquaTabs treat 60 liters for $13. Then when the chemical runs out, you need to buy more. UV purifiers like the SteriPen Ultra can only treat one liter at a time. This works just fine for immediate drinking needs for one person, but for large groups of people or managing water at a camp, the process becomes slow and annoying.
Straw filters have a similar limitation. They can be an excellent choice for personal use, but since they only filter water as you drink through it, they do not work for groups or camps.
With the Sawyer Mini, Lifestraw Flex and Sawyer S2, one can filter water for others and into different vessels, but it requires you to fill the provided soft bottle and manually squeeze the water through the filter into separate containers, which can tire out your squeeze strength. We found this process slow and cumbersome and prefer to use the MSR TrailShot to fill bottles from the source.
Gravity filters excel at treating water for groups of people. They usually include 2L to 6L bags, and can quickly process this amount of water at once. It takes under five minutes for the Platypus GravityWorks to treat an entire four liters. These backpacking water filters are ideal for groups and trips that involve a basecamp since they also provide a way to store water and have it at the ready for cooking.
Imagine this common scenario: You are backpacking and come to a stream crossing where you can refill water. Your next water source will not be for another six miles, so you need to maximize this source. Ideally, you will drink a good amount of water now, and fill up all of your bottles and/or bladder reservoirs now to carry with you to drink until the next source. This is when the time it takes to treat water matters. Aquamira drops, one of the lighter systems, takes up to an hour to fully treat for everything including Cryptosporidium. This chlorine dioxide system kills most pathogens in the first 15 minutes, but that still requires a wait time that cuts into precious hiking hours.
The most immediate systems are the straw filters, the Lifestraw, the Sawyer Mini, Sawyer S2, MSR TrailShot and the Katadyn BeFree where you can drink directly through the filter. However, the water flow through some of these filters is slow, and you can't carry very much water with you unless you decide to dedicate a vessel to carrying dirty water.
Most pumps can filter a liter in a little over a minute, which is preferable, and they can treat unlimited amounts of water, unlike the systems that are limited by a specific bottle or container. The Guardian was the fastest pump system followed closely by the Hiker Pro.
The fastest systems actually surprised us: the Katadyn Gravity Camp 6L filtered one liter in 40 seconds, followed closely by the Platypus GravityWorks and the MSR AutoFlow, each filtering a liter a minute. At first we thought a gravity system would require the most waiting around, but in fact, they worked the quickest, taking one minute to filter one liter and 3:05 for an entire gallon through the GravityWorks. And better yet, you don't have to sit there and pump it, so you can fill it up and let it start working while you take a snack break or set up camp. We think that gravity filters are the bee's knees and everyone should seriously consider owning one for their filtration needs. Even though chemical treatments are simple, the pump and gravity backpacking water filters are the best for a hiker on the go.
Weight is a huge concern since you will most likely be lugging your water treatment system with you on long hikes. Hiking is more enjoyable with less weight on your back, so wisely selecting a treatment system that does not weigh more than your sleeping bag is a huge plus. Rather than go by the manufacturers' specs, we weighed each system individually, including all the accessories and carrying cases that would be brought with them into the backcountry, to give you the most accurate idea of how much the system adds to your pack.
The lightest backpacking water filter system is the Aquamira Frontier Max weighing a scant 2.1 ounces. However, our favorite lightweight filter option is the Sawyer Mini at 2.5 ounces that includes its small bottle. Chemical treatments are also very light as well as compact and almost unnoticeable in your pack. Aquamira Water Treatment Drops weigh 3 oz with their carrying caps. If you only want to bring a couple of individually wrapped chemical tablets, the MSR AquaTabs weigh just 0.2 oz for the whole package.
Next comes the LifeStraw at 2.7 oz and the MSR AutoFlow, the lightest of the gravity filters at 10.9 oz. The heaviest and bulkiest systems were by far the MSR Trail Base at 17.6 ounces and the MSR Guardian at 22 ounces.
Once you've used a filter in the field, it will inevitably be heavier than when you started out, since it is challenging to get all traces of water out of the filter. Unless you have all day to wait around for it to dry out, consider doing your best to dry it overnight to get all that extra water weight out. If you're in cold climates, it's best to bring your filter into your tent, so it doesn't freeze; while you're at it, take it apart so it can dry if possible.
We did not specifically score the products on water taste in this review but still think this is something to take note of. Though the taste is not a huge factor to consider when purchasing a water treatment system, there is a noticeable difference between certain treatment methods. The chemical treatments all change the flavor of water slightly. Iodine is famously horrible tasting, but the taste-neutralizing tablets do a fairly good job of counteracting it. Chlorine dioxide does not add an entirely unpleasant flavor to water, but it has a small background, pool-like taste to it.
Many filters improve the taste of water by cleaning out chemicals and heavy metals and neutralizing odors. The Lifestraw Flex has a carbon component that is meant to help neutralize odors and tastes. The SteriPEN is the one system that doesn't change the flavor at all, positively or negatively. The Sawyer S2 improves the taste of water but deposits some foam particulate from its filter into the water, which made it less desirable to drink.
Water treatment has come a long way in the last decade, and there is no one backpacking water filter system that is best for every application. However, there are some very fantastic and versatile options out there. To create the best review of backpacking water filter and treatment methods, we carefully researched and chose top models and then put them up to a series of rigorous tests in the field and the lab. We weighed each one on our scale, timed each one to see how long it took to treat a liter of water in a controlled test and tasted the outcome of each one to see if it was changed. We polled other backcountry enthusiasts, including Appalachian Trail and Pacific Crest Trail thru-hikers, to see what treatment methods they chose to carry with them in the backcountry for months at a time. Then we carried them with us in the backcountry on multiple overnight camping trips, day trips and overseas to evaluate how they perform in real-world applications and came up with detailed comparison results.
— Jessica Haist
Still not sure? Take a look at our buying advice article for tips.