Updated November 2017
Our team of experts is at it again! We caught wind of the new Sawyer S2 Foam and promptly added it to our review. Just in time for the holidays and the incredible backpacking trips you're planning to go on, we've perused the market to ensure that our selection remains current and offers you the most, whether you're on a budget or looking for the best to filter out viruses. While the technology expands, the once omnipresent pump filters are opening the door to other varieties, including gravity induced filters, or filters that utilize ultraviolet light. Have a large group you need to carry and filter lots of water for? Prefer to go fast and light and drink directly from puddles? Or are you going to work overseas where water sources will be questionable? Read on for the answers to your questions!
Best Overall Model
: Protozoa, bacteria, Cryptosporidium | Weight
: 12 oz
Fast treatment time
Easy to use
Requires little maintenance
Can treat and store up to 8L
Hard to close
Hard to collect water from some sources
For the third year in a row, the Platypus GravityWorks
wins the Editors' Choice Award as a stand out product. It is incredibly easy to use, lightweight, packs down relatively small, and requires little maintenance. There are several other similar gravity filter units in this review, but we like the "clean water bag" that is included and is a bonus for lots of water storage and keeping clean water on hand and ready when you want it instead of waiting for it to filter. The ability to treat small or large amounts of water quickly, as well as store and transport it, is the GravityWorks'
advantage. If you're traveling to developing countries outside of the U.S. and Canada, you may want a water treatment system that treats viruses, as this one doesn't. This filter was closely followed in scoring by the MSR AutoFlow Gravity Filter
, which has the same filter unit and has shed a few ounces this year, but no extra capacity. The Katadyn Gravity Camp
is hot on their heels as a contender for the best and is the fastest of the gravity filters.
Read review: Platypus GravityWorks
Best Bang for the Buck
: Protozoa, bacteria, Cryptosporidium | Weight
: 2.5 oz, including bottle
Doesn't treat large quantities well
Needs regular backflushing or gets hard to use
The Sawyer Mini
knocks it out of the park regarding price to weight and performance ratio. When it comes to performance-to-price ratio, our Best Buy Award winner is leagues ahead. Ringing in at $25, good for 100,000 gallons of use, and it is one of the lightest and smallest treatment methods in this review. It's total trail weight of 2.4 ounces if you carry the straw attachment and a 16 oz soft bottle, or just 1.4 ounces for the filter, this filter is light. We like the Mini
over the LifeStraw
, which can only be used as a straw. More versatile, the Mini
can be used as a straw to drink from a source, it can be screwed onto a small-mouthed bottle to drink from, or it can be attached inline to a hydration bladder hose. At this price and weight, there is no reason not to protect yourself from possible water contaminants while in the backcountry. The Sawyer S2 Foam Filter
is also an excellent and inexpensive choice that also treats viruses for international travel.
Read review: Sawyer Mini
Top Pick for Ultralight
Aquamira Water Treatment Drops
: Bacteria, protozoa, and viruses | Weight
: 3 oz
Small, light and economical method
Effective on viruses
Somewhat long incubation time
Adding chemicals to water
Made for the ounce counters of the world, the Aquamira Water Treatment Drops
is a lightweight choice to get the job done. If the thought of the initial price of a filtration system has your head spinning, these will give you the means to get out in the backcountry on a budget. Utilizing the chlorine dioxide treatment method, fifteen dollars covers two single ounce bottles of drops, which treat 30 gallons. This is an effective and lightweight system that earns our Top Pick for Ultralight users. This system is small, light, and can treat any amount of water, large or small. You can bring it on your international travels because it eliminates viruses and also kills Cryptosporidium if you wait one hour, which iodine, the other leading chemical treatment, does not. Aquamira
is a top choice for ultralight backpackers and long distance hikers, but also a great choice if you're heading out for a leisurely backpack. The only downside is that this treatment does not filter out particulate, so it is best used in locations with relatively clear water. Other lightweight options in this review that don't involve chemicals are the MSR TrailShot
and the Sawyer Mini
Read review: Aquamira Water Treatment Drops
Top Pick for International Travel
MSR Guardian Purifier
: Bacteria, protozoa, and viruses | Weight
: 22 oz
There is a new kid on the block, the Porsche of water pumps, the MSR Guardian
. This purifying pump takes our Top Pick Award because it is super easy to use and maintain and most importantly it is the only hand pump filter that purifies viruses. It is also one of the fastest in our tests: our testing determined that this filter could fill a liter bottle in 47 seconds and we were impressed by the smooth handle operation. This unit back flushes with each stroke, so it is always maintaining the same level of performance. This is a great choice for an urban, rural, or wilderness international traveler. It is painless to pull out the Guardian to give your drinking water some extra security. We would not recommend taking the Guardian on backcountry trips in Canada and the U.S. since viruses are not much of a concern there. It weighs in at a hefty 22 ounces and has a steep price tag of $350. This is a worthy investment to protect yourself from pathogens that are more commonly found in developing countries.
Read review: MSR Guardian
Top Pick for Trail Running
: Bacteria and protozoa | Weight
: 2.3 oz
Instant water treatment
Small treatment capacity
In the age of ultra-marathon trail runs and events like the Leadville 100, new products are being designed to get you water fast for long days out on the trails. The Katadyn BeFree
was designed for just this purpose. Weighing in at 2.3oz, this filter can be rolled up and put in your pocket or vest no problem; then, you can just pull it out when you come upon a water source, fill it up and chug. This is an excellent option for any active day out where you'll be near water for boating, fishing, or even mountain biking. The BeFree
is not the best option for long backpacking trips or filling up water for groups since it can only treat 20 ounces of water at a time.
Read review: Katadyn BeFree
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. We think that three of the criteria we evaluated for are equally important: weight, treatment capacity and ease of use. Weight is important because when traveling in the backcountry, it is desirable to have a compact and lightweight system and not to have a heavy and clunky filter weighing 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 easy 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.
Reliability and effectiveness are related, but are slightly different; there are a few different sub-headings that fall into this category.
: 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, a system that treats viruses is strongly recommended. Here is a quick look at five systems that do handle viruses:
- Chlorine Dioxide (tablets or drops) like Aquamira
- New gravity filters are now treating viruses too, like the LifeStraw Mission
The Guardian was overkill in pristine alpine meadows in the Sierra Nevada. It would be a better choice for international travel in developing nations.
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 are effective on various types of organisms. The main difference in effectiveness in the systems we reviewed is whether or not a system eliminates viruses or the hard-shelled (meaning hard to kill) protozoa Cryptosporidium.
All treatment methods in this review will protect you from harmful micro organisms but it's best to avoid areas where you can see the contaminant in the water - or at least fill up upstream!
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 Sweetwater
are easy to rely on. 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 Sweetwater filter handle is the most delicate of the ones we tested.
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
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 MSR Sweetwater
, which treat approximately 750 liters.
The Katadyn Vario is easy to pump and fast! We really like the comfortable shape of its handle.
Systems that had reported issues of durability were the SteriPEN
, Katadyn BeFree
and the Katadyn Vario
. One pair of hikers said the SteriPEN
was ruined after getting rained on (although the new Ultra
is watertight), and other users reported random malfunctions and glitches with the light unit. The Vario
has been said to leak heavily from between the filter casing and the pump housing after heavy use, though we did not observe any of these problems with either model. It has also been reported that the BeFree's
bag has ripped after only a few uses - we did not experience this either, but the materials do seem delicate.
The SteriPEN Ultra uses ultra violet light to get rid of harmful microorganisms.
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 this one are the 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 Trailshot allows you to drink directly from the water source and reach more difficult to reach sources.
The MSR Miniworks EX
, Katadyn Vario
, and the Sweetwater
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 also needs to be done fairly often, 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.
It's pretty clear when the Ultra is trying to tell you that you can drink your water.
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.
allow for a seemingly endless amount of water. You can pump as much or as little as you need. All filter units need to be replaced eventually, 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.
You can use the TrailShot to fill your group's water bottles, but it takes a little more time and hand strength than other methods.
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 liters to be treated; 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.
You can share the filtration of the mini with your friends, but it is not the quickest or most efficient method of filtering large amounts.
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.
Mick Pearson drinking out of a muddy pond with the Lifestraw. Because it is so short it makes it difficult to drink out of places that are hard to reach because of mud or high banks.
With the Sawyer Mini
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.
To get the full 20 ounces from the S2 requires a lot of squeezing.
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.
The 4 liter bag and 1500 liter cartridge life make the Autoflow score high in the treatment capacity department.
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.
Little puddles in granite pockets are a perfect place to get water while alpine climbing with this model.
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 Katadyn Vario
was the fastest pump system followed closely by the Guardian.
The Vario can attach to most vessels, including MSR bladders and is the fastest pump filter we tested.
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.
The Gravity Camp by Katadyn is so fast there is virtually no wait time to fill a liter.
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 Katadyn BeFree
at 2.3 ounces that includes its small bottle, followed closely by the Sawyer Mini
with its bottle at 2.5 oz. 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.
The MSR TrailShot and Katadyn BeFree are both marketed for trail running, but the BeFree is much lighter and more compact than the TrailShot.
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 Katadyn Vario
at almost 20 ounces and the MSR Guardian
at 22 ounces.
The Sawyer Mini (and its included straw) next to the LifeStraw (top) for size comparison. The Mini is much lighter and more compact than the LifeStraw, and in our opinion, more versatile as well.
Once you've used a filter in the field, it will unavoidably 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.
These small tabs purify two liters of water at a time.
Many filters improve the taste of water by cleaning out chemicals and heavy metals and neutralizing odors like the Vario
. 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.
Some water treatment systems offer a pre-filter option such as the SteriPen Water Bottle Pre-Filter
which helps get large particulates out of the water to make sure the light penetrates to all of the water. The MSR Sweetwater Microfilter
filters out the particulates before it reaches the filter to help keep it cleaner for longer.
Dan Sandberg uses the Hiker Pro to filter water from a running stream, Rocky Mountains, Colorado.
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 as well as day trips to evaluate how they perform in real-world applications and came up with detailed comparison results.