Water Filter Features Editor's Score Buy On Amazon.com

Platypus Gravityworks

  • Type: Gravity Filter
  • Weight: 11.5 oz
  • Lifespan: 1,500 liters
  • Best for: Hiking, backpacking, camping
  • Filter size: 0.2 microns
  • Effective against: waterborne bacteria and protozoan parasites, but not effective against viruses

Sawyer Mini

  • Type: hollow fiber filter
  • Weight: 2 oz
  • Lifespan: 100,000 gallons
  • Best for: Individuals and groups
  • Filter size: 0.2 microns
  • Effective against: waterborne bacteria and protozoan parasites, but not effective against viruses

MSR Autoflow

  • Type: gravity filter
  • Weight: 10.9 oz
  • Lifespan: 1,500 liters
  • Best for: hiking, backpacking or camping with large groups
  • Filter size: 0.2 microns
  • waterborne bacteria and protozoan parasites, but not effective against viruses

Katadyn BeFree

  • Type: hollow fiber filter
  • Weight: 3.2 oz
  • Lifespan: 1,000 liters
  • Best for: lightweight backpackers, hikers or runners
  • Filter size: 0.1 microns
  • Effective against: waterborne bacteria and protozoan parasites, but not effective against viruses

Lifestraw

  • Type: Survival Straw
  • Weight: 2oz
  • Lifespan: 1,000 liters
  • Best for: emergencies, bugout bags
  • Filter size: 0.2 microns
  • Effective against:waterborne bacteria and protozoan parasites, but not effective against viruses

Look, no one wants to be That One Guy Who Drank Nasty Water and Had Diarrhea From Hell.

Most outdoor enthusiasts know that when you’re out in the backcountry, finding a good water source is just half the job. You also have to make sure that the water source is clean enough to drink. While pristine water sources like mountain streams and snowmelt are relatively clean (and seriously refreshing after hours on the trail), other bodies of water could be riddled with sediments, agricultural and industrial waste and good ol’ bacteria, parasites and protozoa that can cause a myriad of diseases.

And the thing is, sometimes, these possibly contaminated water sources are all you have when you’re out on the trail.

Thankfully, there are backpacking filters to keep your water clean and drinkable.

Designed to be taken on the road, most— if not all— of these filters can take out 99.999% of bacteria, protozoa, parasites, and particulates in the water. They also significantly reduce the water’s turbidity. Lastly, these filters are also very portable, efficient and unlike chemical purification methods, don’t affect the water’s taste.

Choosing The Right Backpacking Water Filter

Backpacking water filters come in all shapes and sizes. These filters may be similar in function, but their differences can also make or break their performance.

Choosing the right one that fits your needs is crucial for a smooth and enjoyable time outdoors, so we took the liberty of reviewing the best water filters out on the market.

We did extensive research, scouring hundreds of reviews and testimonials from backpackers, section and thru-hikers, athletes and even preppers while also looking into our own personal experiences on the trail. We considered each filter’s weight, ease of use, speed, effectivity and over-all price-performance ratio and then narrowed it down to the cream of the crop.

We proceeded to put these products to the test by heading out on a backcountry hike, and ended up with 5 of the best ultralight backpacking water filters out there:

PLATYPUS GRAVITYWORKS

Great For:

Big groups, campers, hikers

Pros:

Gravity-fed; no hand pumping required
Able to filter up to 1.5 liters/minute
Lightweight compared to pump filters
Has a reservoir for clean water
Quick backflushing that can be done on the field
Convenient storage
Has adapters for various water storage devices

Cons:

Does not remove viruses, iron, sulfur, other chemicals or simple compounds
Ziplock top used to secure dirty water reservoir can be cumbersome
Difficulty gathering water from shallow source
Has a lot of small accessories
Ultrafiltration hollow fiber membrane could be susceptible to freezing

Filter Lifespan:

1,500 liters

What People Are Saying:

189 reviews on Amazon with 91% 4-5 star ratings

For a lot of backpackers, gravity water filter systems were a revelation. Imagine, no more tired hands from all the pumping! The Platypus Gravityworks is one of two awesome gravity filters in this review and suffice it to say that it and the MSR Autoflow did not disappoint.

What we love about the Platypus is that it’s got two reservoirs, one for dirty water and another for the clean, filtered water. That means you can store and carry clean water back to camp with you. Large volumes of it, too, as the Platy is available in 2-liter and 4-liter systems (we used the 2-liter system for this review). It’s great for big groups or if you’re going on a long-haul trek with few rest stops in between. Both reservoirs are made of plastic— tough but flexible— and can easily be cleaned and then rolled for storage.

What we didn’t love about it is that it has a lot of little parts. Literally a small issue in the grand scheme of things, considering that the Platypus is an excellent water filter, but when you’re out in the backcountry assembling a filter with so many tiny accessories, it can be a chore. Be that as it may, these little parts include the various adapters that allow you to use your Platy filter in a lot of ways, so you just have to be organized on the trail to avoid contaminating your adapters.

The dirty water bag is secured by a ziplock top. It can be quite difficult to close or even open the bag once you’ve filled it to capacity or after multiple uses. The bag itself, however, has sturdy straps so you can use those to hold the bag up or hang it on an elevated place, like a tree branch.

Its manufacturers proudly state that the Platypus can filter 1.5 liters per minute. It had been raining further upstream when we tested the product, so the water source was, at best, the color of fresh latte. All the better to put the products to the test.

The Platy worked at a decent speed but it wasn’t what we expected. In our experience, we got about 1.75 liters in 2 minutes— that’s barely a liter at half the time. On the plus side though, it consistently delivered the same volume after repeated use and didn’t slow down.

The system can be cleaned right on the field through backflushing, which was a breeze. Other product reviews state that they have a bit of difficulty with the backflushing, but as per our experience, it was quick and easy. It took about 3-5 minutes of continuous backflushing before the water turned clear again.

The Platypus Gravityworks can be used to filter 1,500 liters of water in its lifetime.

All in all, the Platy did great. Its clean water reservoir was convenient and it made backflushing easier.

MSR AUTOFLOW GRAVITY FILTER

Great for:

Big groups, campers, hikers

Pros

Gravity fed – no hand pumping required
Can filter large quantities of water (2L and 4L)
Filters fast at 1.75 liters/min
Has adapters for various water storage devices
Reservoir includes a buckle for additional security from the possibility of popping open

Cons

Doesn’t come with a clean water reservoir
Getting water from a shallow source can be difficult
Does not remove viruses, iron, sulfur, other chemicals or simple compounds
Ultrafiltration hollow fiber membrane could be susceptible to freezing

Filter Lifespan:

1,500 liters

What People Are Saying:

Only 2 reviews on Amazon but both for 5 stars

The second gravity filter in this review is the MSR Autoflow and it met expectations with flying colors. Unlike the Platypus, the MSR doesn’t come with a clean water reservoir, which could be a pro or con however you look at it.

This means that you’ll have to provide a clean water container of your own, which could be a water bottle or a hydration bladder. The kit does have adapters for both, so it’s not a very big problem. While having a clean water reservoir like the Platy does have its benefits, you’ll also have less small parts to deal with, which makes set-up faster and easier. Either way, it doesn’t discount the fact that MSR’s performance was great.

What we love about it is that it filters really fast.

It’s advertised to filter an impressive 1.75 liters per minute. In our experience, we got about 1.5 liters a minute, which wasn’t far off the mark. It yielded the same volume after multiple uses.

The MSR’s dirty water reservoir not only looks sturdy; it feels like it too. The reservoir’s texture has a bit of bite and won’t likely slip from your hands when you’re gathering water from a fast-running source. We loved the fact that you can secure it using a buckle instead of a ziplock because a buckle is less prone to pop open.

Backflushing, however, can be a bit challenging because the MSR doesn’t have its own clean water reservoir. You certainly can’t backflush properly if you’re using a wide-mouthed bottle or a container that’s not compatible with the MSR’s adapters. In our case, we used the Platy’s clean water reservoir together with the MSR’s bottle adapter to gather the filtered water. Thankfully, it was a perfect fit between the two. We had a bit of trouble on the first attempt and had no flow at all. The second try yielded better results. We had a clear flow in about 2 minutes of continuous backflushing.

All in all, the MSR is the faster filter on this list, but you gotta make sure that you have a compatible clean water reservoir for backflushing.

LIFESTRAW

Great For:

Emergency situations, personal survival kits

Pros:

Lightweight compared to gravity and pump filters
Portable
No waiting time for purification
All raw materials are BPA free

Cons:

Can only filter small volumes at a time
Not for large groups
Unable to store clean water
Unable to fill up external containers for cooking, etc
Sucking thru straw is not so easy compared to just drinking water from bottle
Ultrafiltration hollow fiber membrane could be susceptible to freezing
Does not remove viruses, iron, sulfur, other chemicals or simple compounds

Filter Lifespan:

1,000 liters

What People Are Saying:

4,082 Amazon reviews with 94% 4-5 star ratings

Any self-respecting backpacker or prepper would recognize what a Lifestraw is. This light and slender personal filter was originally designed to give developing countries access to clean drinking water. It was also meant to be used as an emergency filter in disaster-stricken areas. Since it’s so portable and relatively cheap, the Lifestraw quickly gained popularity in the backpacking and prepping communities.

And boy, is it portable.

At only 2 ounces, the Lifestraw is exceptionally light and easy to carry around. It takes little space in a bag, making it great for people who are always on the move, like backpackers or hikers. The Lifestraw is also ideal for preppers who want a personal filter in their bug out bag or survival kits. It even comes with a lanyard so you can wear it around your neck. The lanyard itself, however, doesn’t look sturdy enough and if we’re being honest, you’re better off replacing it with a length of 550 paracord. The 550 is more reliable and is something that you can deploy as cordage when the need arises.

The filtration process is pretty straightforward. Unlike other water purification devices, you don’t have to wait for your water to be filtered via gravity or pump. You simply have to find a source (be it a river, stream or puddle) and drink from said source using the Lifestraw. More often than not, it results in going on your hands and knees to take a sip from a body of water, which can be messy or inconvenient. You’d also need a couple of strong sips to get started, so sipping from a shallow water source is tricky.

What’s great is that this device is effective against 99.999% of waterborne bacteria, protozoa, parasites and particulates and can effectively filter as much as 1000 liters of water—- enough for one person for a year. Cleaning it is also simple: all you gotta do is puff out of the filter to expel any nasties that might block it.

And that’s the thing about the Lifestraw.

The simplicity of its design is also its biggest downside. While it’s understandable that the straw was meant for urgent needs and short-term crises, it doesn’t discount the fact that, well, it’s pretty limited.

First of all, it’s a personal filter: you can’t use it for big groups or if you’re bugging out with the family. You’d have to get one Lifestraw each and even then, you still will be unable to store and bring clean water with you. You’d always have to be on the lookout for a water source to drink from, or, as an alternative, lug around unfiltered water in a container with an opening wide enough to accommodate the Lifestraw. You will also be unable to filter water for cooking and other purposes. Using the Lifestraw is pretty okay if you’re staying in one place, but if you’re hiking or camping out? Not so easy.

All in all, the Lifestraw wins in terms of portability. It’s pretty handy to have in emergencies as a personal filter. But if you’re a big group that would consume and store large amounts of water at a time, you might want to look at the other water filters in this list.

KATADYN BEFREE WATER FILTER

Great for:

Hikers, runners, lightweight backpackers

Pros:

Portable
Collapsible
Lightweight
All raw materials are BPA free
Flow rate is very fast compared to Sawyer and others – comes out as fast as you can squeeze it
Has a 1000 L filter life

Cons:

Unable to backflush; you can, however, shake water in the bottle to clean the filter
Can only carry 1L of water at a time
Ultrafiltration hollow fiber membrane could be susceptible to freezing
Does not remove viruses, iron, sulfur, other chemicals or simple compounds

Filter Lifespan:

1,000 liters

What People Are Saying:

84 Amazon reviews, with 73% 4-5 star ratings

The Katadyn BeFree water filter is like the lovechild of the Lifestraw and the Platypus. Like the Lifestraw, it’s very portable. The flask is collapsible so it won’t take so much space in your bag. It can even fit in someone’s back pocket so it’s great for lightweight hikers, backpackers, and runners. Like the Platy, you can actually carry water with you. Sure, it’s nowhere near the Platy’s 4-liter max capacity, but anyone knows that a little hydration goes a long way when you’re on the trail.

The Katadyn BeFree is pretty easy to use. You don’t need a complicated set-up and you can have a drink of water in a jiffy. The filter is attached to the drinking nozzle, so all you have to do is get water, attach the filter and squeeze. Just make sure you don’t contaminate the nozzle’s tip.

Filter size is at 0.1 microns, so it’s effective against most waterborne bacteria, protozoa, and parasites, but won’t do much against viruses. When the filter has already reached its lifespan, you can simply buy a new one. The reservoir itself has a great texture for grip; although it is quite smaller than most, it doesn’t easily slip from your hands, especially when you’re gathering water from a running source. While the reservoir can only carry 1 liter of water at a time, you can use the filter to easily fill up other containers with clean water.

The disadvantage of the Katadyn comes in when it’s time to clean. You can still clean it on the field— you basically fill the bottle with water and shake it clean, or take the filter out and swirl it around freshwater to clear it up. Obviously, unlike gravity filters, you can’t do any backflushing to ensure the quality of the filter. Washing it horizontally can also damage the filter.

Another disadvantage is that the filter is not compatible with a lot of water bottles. You need to be careful not to break or puncture the bottle or the filter would be of little to no use unless you buy a new one. Take note that the Katadyn BeFree doesn’t come in cheap— it costs about twice as much as the Sawyer Mini, which we’ll discuss in a bit.

All in all, the Katadyn BeFree is great for personal use. It just came out on around August 2016, so its technology is still pretty new. That being said, it’s prone to have some growing pains in the R&D department, like issues about quality control and field failures that need to be addressed. It’s pretty great when it works, but it could be a pain in the butt when it suddenly stops working.

SAWYER MINI

Good For: Hikers, Backpackers, Preppers….everyone in the whole wide world, as long as you’re not a very large group

Pros:

Very versatile; it can be used in many different ways
All raw materials are BPA free
Solid technology with great reputation for dependability
Can filter 100,000 gallons
Best price-performance ratio

Cons:

Can only filter small quantities of water at a time
Does not remove viruses, iron, sulfur, other chemicals or simple compounds
Ultrafiltration hollow fiber membrane could be susceptible to freezing

Filter Lifespan:

100,000 gallons

What People Are Saying:

4,082 Amazon reviews with 94% 4-5 star ratings

Last but definitely not the least, we have the Sawyer Mini, which blew all other personal filters out of the water (forgive the pun). You can really tell that Sawyer really put their back into this water filter. It’s so small that it can fit in the palm of your hand, but here’s the kicker:

It can filter up to 100,000 gallons with its backflushing capability.

Let that sink in.

For comparison, the Lifestraw, which is slightly heavier than the Mini at 2 ounces, can only filter 1000 liters or 264 gallons.

There’s a lot of things to love about the Sawyer Mini.

First, it’s so versatile. It comes with a sturdy pouch that you can attach to the filter, allowing you to take the water wherever you go. The reservoir is also collapsible so you can roll it up when not used.

You can drink directly from the reservoir with the filter attached, or you can use the system to filter water into other containers. Yes, it can be used to filter several bottles of water, although it’s not as efficient compared to the gravity filters featured in this review.

Next, the system comes with a straw so you can also use the filter to directly drink from a water source, like how you would with a Lifestraw. The catch is, you won’t necessarily have to get down and dirty. The Sawyer Mini can be screwed on most plastic water bottles. As long as you can squeeze the bottle, you can definitely drink from it. This is the usual problem with many water filters and we are ever so glad that Sawyer came up with this solution.

Another advantage is that you can also use the Sawyer inline with your hydration bladder.

The kit comes with a syringe that you can use to backflush the filter.

Perhaps the only disadvantage to the Sawyer Mini is that the pouch can’t carry more water. It can only hold 16 ounces at a time so filtering large amounts of water can be pretty exhausting after a while. To be fair, though, the Sawyer Mini was designed as a personal water filter. And there’s definitely a workaround for it, too. Since the Mini can be screwed onto most plastic and soda bottles, you can simply replace the pouch with a bigger reservoir.

All in all, the Sawyer Mini ended up being the best of the bunch, thanks to its versatility and excellent price-performance ratio. We highly recommend it to anyone who loves the outdoors.

How Do Water Filters Work?

Backpacking water filters may have their differences, but they all have one thing in common: they use hollow fiber membrane technology.

It works like this:

Think of hollow fiber membranes as tiny tubes, like straws. Along the tubes’ walls are thousands, even millions of tiny pores. These pores are so tiny that anything bigger than 0.2 or 0.1 microns can’t go through. To give you an idea of just how wide a micron is, an average human hair strand is around 10-200 microns wide.

So yes, these pores are ridiculously small, and they are very effective against harmful microorganisms since most bacteria and protozoa are bigger than 0.2 microns.

The filtration then happens when dirty water passes through the hollow fiber membranes either through gravity, sipping or squeezing.

What Types of Microorganisms Do These Filters Protect You From?

Most filters are effective against the following microorganisms:

Salmonella

According to the CDC, 1.2 million salmonella cases are recorded each year, with around 450 cases ending in death. Salmonella is a type of bacteria that live in animal and human intestines and is eventually excreted in feces. You can get salmonella infection through improper food or water handling.

Common signs and symptoms of salmonella infection include diarrhea, fever, and abdominal cramps within 8-72 hours of contact. When untreated, this could eventually lead to severe dehydration and shock.

E.Coli

Escherichia coli (or E.Coli, as it is commonly known) is also a type of bacteria found in the gut. While most E.Coli strains are harmless, other types can cause severe gastrointestinal upset, pneumonia and even urinary infections.

E.Coli can be transmitted through food that is not thoroughly cooked, unpasteurized milk and, of course, contaminated water, especially those found in lakes, ponds or sources that can come in contact with animal manure.

Signs and symptoms include bloody diarrhea, vomiting, and even acute kidney failure in some cases.

Giardia

Giardia is a kind of protozoan parasite. It has a tough shell that protects it from chlorine disinfection. Giardia is most often transmitted through contaminated water and is one of the leading causes of gastrointestinal disease in the US. Giardia infection is common during the summer. Hikers, campers, and backpackers are especially at risk.

Signs and symptoms of Giardia infection include loose, greasy stools, flatulence, and abdominal cramps.

Cryptosporidium

Cryptosporidium or crypto is a microscopic parasite. Like Giardia, it also has a tough shell that is impervious to chlorine and is one of the leading causes of waterborne diseases in the States. Infected people can come down with watery diarrhea within 2-10 days of contact.

Why Can’t Filters Get Rid Of Viruses?

If you’ve noticed, all filters in this list can’t get rid of viruses.

This is because viruses are usually smaller than bacteria and parasites. You will need a device with an even smaller pore size, usually at 0.01 microns. Unfortunately, outfitting gravity and straw filters with 0.01 microns is somewhat counterproductive and difficult since water flow would be very slow.

That being said, only pump-assisted devices are made with pores this size. They’re actually no longer considered as filters but are now classified as purifiers.

If you’ve noticed, we left out the pump filters because while they’re very effective, pumps also weigh significantly more (none of these ultralight filters weigh more than 12 ounces, while the lightest pump filter can easily weigh 20 ounces or more). Plus, pumping takes a lot more effort.

The good news is, waterborne viral diseases are not an issue in the States, where water standards are high. If you’re traveling to developing countries, however, you might want to look into pump filters or other modes of water purification.

The Final Verdict

When it comes to choosing the right backpacking water filter, you have to keep in mind that one size does not fit all. A filter that might be perfect for a solo backpacker might not be the best fit for those hiking in groups. You really have to identify your needs and priorities.

We ended up picking out the best ultralight water filters for different types of outdoor enthusiasts. If you’re a solo backpacker or cross-country runner, there’s the Katadyn BeFree. Its collapsible squeeze flask can carry up to 1 liter and you can conveniently carry it with you as a personal filter.

If you want a personal filter that you can use even in emergencies, you can whip out the Lifestraw. It’s light and portable and a must-have for every bug out bag.

The Sawyer Mini is the most versatile of the bunch: you can use it as a personal or group filter and really is the best bang for your buck out of all the filters in this list.

If you’re a big group, there are the two gravity filters: Platypus Gravityworks and MSR Autoflow. It was a tight competition between these two. MSR is the faster filter, but the Platy has the advantage of having a clean water reservoir. Whatever floats your boat, you can’t go wrong with these two.

It’s important to note that one should follow the manufacturer’s directions to ensure that the filters last long and prevent contamination. These filters have their own pros and cons, and we hope that this review would help you in choosing the right filter that fits your needs.

So, these are our top 5 ultralight backpacking water filters. What’s yours? Let us know in the comments below!

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