10 Best Backpacking Water Filters

What are the best water filter and water purification treatment systems used by backpackers? That really depends on your preferences, the quality of the water you need to filter or purify, and the number of people you need to treat water for. For example, squeeze-style water filters, UV purification, and filter bottles tend to be good for solo users and clear water sources, while chemical purification and pump filters/purifiers are good for larger groups and riskier or murkier water sources. Cost and filter longevity are also worth considering.

Make / ModelTypeLifetime (in Liters)Price
Sawyer SqueezeSqueeze Filter100,000$37
HydroBlu Versa FlowSqueeze Filter100,000$22
Katadyn BeFreeSqueeze Filter1,000$40
Aquamira Purification DropsChemical Purification120$15
Platypus Gravity WorksGravity Filter1,500$110
Katadyn HikerPump Filter1,100$75
Steripen UltraUV Purification8,000$110
Grayl GeopressSqueeze Filter250$90
MSR Miniworks EXPump Filter2,000$90
MSR GuardianPump Purifier10,000$350

Here are the 10 best backpacking water filters and water purification systems we recommend for backpacking, hiking, and camping in 2021.

1. Sawyer Squeeze Water Filter

Sawyer Squeeze Water Filter System

The Sawyer Squeeze Water Filter System includes the Sawyer Squeeze Filter, two 32 fl. oz. pouches, a cleaning coupling, and additional accessories for gravity and inline use. Like the Sawyer Mini, you can drink directly from the Sawyer Squeeze but most people squeeze untreated water through it from a soft bottle to a clean container. The filter uses a hollow-fiber membrane filter that removes 99.99999% of all bacteria, such as salmonella, cholera, and E.coli, and removes 99.9999% of all protozoa, such as giardia and cryptosporidium. The filter itself weighs 3 ounces. Read the SectionHiker review.

Check out the latest price at:
REI | Amazon

2. HydroBlu Versa Flow Water Filter

Hydroblu Versa Flow Water Filter
The HydroBlu Versa Flow Water Filter can be used as an inline, gravity, squeeze, or straw filter without requiring the purchase of additional syringes, connectors, adapters, or replacement gaskets; it’s compatible with all standard 28mm soda bottles and reservoirs including the CNOC Vecto; it comes with color-coded end caps to keep the intake and output spouts clean; it doesn’t leak between uses, and it has a transparent inspection window so you can determine when it needs to be cleaned. The Versa Flow 99.9999% of waterborne bacteria such as salmonella, cholera, and E.col and 99.9% of protozoa including Giardia and Cryptosporidium. Read the SectionHiker review.

Check out the latest price at:
HydroBlu | CNOC | Amazon

3. Katadyn BeFree Water Filter

Katadyn BeFree Water Filter
The Katadyn BeFree Water Filter can be used as a squeeze filter or hung for group use as a gravity filter if you purchase the 3L version. It has a 0.1-micron microfilter that is EPA tested to remove protozoa (99.99%) and bacteria (99.9999%). It can filter water up to 2 liters per minute, which is very fast for this style of filter. An integrated wide-mouth soft bottle, available in three different sizes, 0.6L, 1 liter, and 3 liters, is easy to fill in streams and folds up compactly when not in use. Weighing 3.5 oz total, the filter alone has a life expectancy of 1000 liters. Read the SectionHiker review.

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REI | CNOC | Amazon

4. Aquamira Water Purifications Drops

Aquamira Water Purification drops
Aquamira Water Treatment Drops use chlorine dioxide (used in municipal water treatment plants) to kill 99.9% of bacteria, viruses, and cysts, including cryptosporidium and giardia. Each package of Aquamira contains two bottles, Part A and Part B, which you mix together before treating your water. The drops are effective in clear, muddy, warm, and cold water and have a shelf life of five years, making them an excellent solution for international travel, hiking, backpacking, and emergency preparedness. Each Aquamira package contains enough drops to treat 30 gallons of water. Many people carry Aquamira as a backup in case their water filter breaks or for purifying several liters of water at once. Read the SectionHiker review.

Check out the latest price at:
REI | Amazon

5. Platypus Gravity Works

Platypus Gravity Works
The Platypus Gravity Works water treatment system is a gravity filter that includes two x 4 liter water reservoirs, a water filter, and connecting hoses arranged in a gravity filter configuration. It’s ideal for filtering water for couples or families when you need to filter a large quantity of water quickly. The Gravity Works filter physically removes particles, protozoa, and bacteria down to 0.2 microns in size, including giardia, salmonella, and cryptosporidium. Quick-disconnect valves and a hose clamp make cleaning easy. Filtration speed is over 1 liter per minute and requires no effort once the “dirty” bag is hung. The expected filter lifetime is 1500 liters of water. The entire system weighs 10.75 ounces and stows smaller than most 1L bottles. Read the SectionHiker review.

Check out the latest price at:
Backcountry | REI | Amazon

6. Katadyn Hiker Water Filter

Katadyn Hiker Water Filter
The Katadyn Hiker Water Filter is a pump-based filter that removes particulates, protozoa, and bacteria down to 0.2 microns in size, including giardia, salmonella, and cryptosporidium. It includes a pre-filter at the hose outlet that filters to 150 microns, good for use with cloudy or sediment-filled water, which removes large contaminants before they reach the main filter and increase its life span. Quick-connect fittings permit removal of input and output hoses: the hoses also connect directly to hydration reservoirs with 0.25 in. drink tubes. The expected filter life is 1150 liters before replacement is required. The Hiker weighs 11 ounces.

Check out the latest price at:
Backcountry | REI | Amazon

7. Steripen Ultra UV Water Purifier

Steripen Ultra UV Water Purifier
The Steripen Ultra is a water purifier that uses ultraviolet light to neutralize bacteria, protozoa, and viruses that can make you ill. The Ultra is USB rechargeable and fits in narrow or wide-necked bottles. It’s also one of the best solutions for purifying cold water, which will create tiny holes in most filters if it freezes when the filter element is damp in cold weather, thereby destroying them. To use it, you simply dip it in a container of water and stir, until an indicator lamp signals that the water is purified, after about 90 seconds. Weighing just 4.94 ounces, the Steripen Ultra has a UV lamp life of 8000 uses.

Check out the latest price at:
Backcountry | REI | Amazon

8. Grayl GeoPress Water Purifier Bottle

Grayl Geopress

The Grayl GeoPress is a bottle-based water purifier that removes Protozoa, Bacteria, and Viruses from water sources. The GeoPress has an outer bottle and an inner bottle, with a filter at one end and a drinking spout with a screw-on top at the other. To use it, you pull the inner bottle out of the outer bottle, fill the outer bottle up with suspect water, and then push the inner bottle into the outer bottle like you would a french press. When finished, you can carry your purified water and sip it directly from the bottle for added convenience or decant it to a different container. Read the SectionHiker review.

Check out the latest price at:
Backcountry | REI | Amazon

9. MSR Miniworks EX Water Filter

MSR Miniworks Water Filter
The MSR Miniworks EX is a pump style water filter that screws onto wide-mouth Nalgene bottles and soft canteens. While the MiniWorks is heavier than simpler squeeze-style water filters, it’s a better solution for filtering turbid, cloudy, or tannic water sources like snowmelt, spring thaw, or algae-infested ponds and turning them into clear and pleasant tasting water. That’s because the Miniworks is a three-stage filter, with a pre-filter that removes larger solids, a ceramic filter to remove microorganisms, and a charcoal filter to remove unpleasant odors and tastes. Weighing 17 ounces, the Miniworks has an output of 1 liter per minute and filters out contaminants down to 0.2 microns in size. The expected filter lifetime is 2000 gallons. Replacement filters are also available. Read the SectionHiker review.

Check out the latest price at:
REI | Amazon

10. MSR Guardian Purifier

MSR Guardian Water Purifier

The MSR Guardian is the most sophisticated and effective water purifier available today. Self-cleaning, it has a high flow rate and generates remarkably good tasting water. While it is an excellent tool for backcountry use and international travel to countries with suspect water, it’s also quite a nice product to have on hand for emergency preparedness at home. The Guardian physically removes viruses, bacteria, protozoa, and particulates, including hepatitis A, E. coli, giardia, and cryptosporidium, and has a pore size of 0.02 microns. Weighing just 17.3 ounces, the Guardian has a self-cleaning filter that constantly purges itself while you filter water so you never have to backflush or scrub the filter element. It also has an exceptionally high flow rate of 2.5L per minute, making it ideal for individual or small group use. Read the SectionHiker review.

Check out the latest price at:
Backcountry | REI | Amazon

How to Choose a Backpacking Water Filter or Purifier

Many natural water sources contain microscopic organisms that can cause illness in humans. Most water filters intended for backcountry use will remove bacteria and protozoa, including giardia and cryptosporidium from these water sources. This is usually sufficient in the United States, Canada, and the UK. Viruses, often found in international water sources, are hard to remove because they are so small. Finer grained filters called purifiers are needed to remove them. They also can be neutralized with chemical purification agents such as chlorine dioxide or ultraviolet light.

There are a wide number of different water filter and purifier types available. Unfortunately, none of them are foolproof or perfectly suited for all kinds of trips and locales. They also differ in ease of use, the length of time it takes for them to process water, and whether they’re good for solo or group use. Here’s a brief summary of the different types and their strengths and weaknesses, with several examples to illustrate the available products in each category.

Squeeze Water Filters

Squeeze filters are single-stage filters that are good for removing bacteria and protozoa, but not viruses. They’re best used with clear water sources that are low in particulates and suspended organic matter to prevent clogging. Processing speed depends on the size of the “dirty” water bottle coupled with the filter and how much pressure the user exerts to push water through it. However, squeeze filters typically slow down with use and must be back-flushed with a cleaning syringe regularly to maintain their flow rate. Some examples:

Gravity and Inline Water Filters

Gravity water filters make it possible to process larger quantities of water at once using the power of gravity. A large water reservoir, called “the dirty bag” is hung from a tree with a hose leading to a water filter. The output of the filter flows out another hose to a clean reservoir, called the “clean bag.” A squeeze style, single-stage filter is typically used. Gravity filters are good for couples and small groups. An inline water filter uses a similar setup, but the user suck on the output hose rather than running it to a clean bag. Some examples:

Bottle and Straw Water Filters

Bottle and straw filters usually use the same single-stage, hollow fiber filters used by squeeze, gravity, and inline water filter systems. The user sucks water stored in a bottle or directly from the water source through the filter, rather than transferring it to secondary storage. They are best used by individuals in places where water is abundant. Some examples:

Pump Water Filters and Purifiers

Pump water filters filter out bacteria and protozoa, while pump water purifiers can also remove viruses. They have hand pumps that force water through the filter and out to secondary storage for future use. While pump filters do require some elbow grease to operate, they usually filter water quite quickly and are suitable for use by couples as well as individuals. Most have a pre-filter at the end of the hose that you drop into the water source to remove particulates and organic matter. This can be very handy when you can’t actually reach the water source, like down a steep embankment. They can also be cleaned and replacement filters are usually available. Some examples:

Chemical Water Purification

Chemical water purifiers are available in tablet or liquid form. The best chemical ingredient is chlorine dioxide, which has virtually no taste or color and kills bacteria, protozoa, and viruses. Chemical purification is best used by individuals rather than couples or groups because it takes anywhere from 15 minutes to 4 hours to fully purify water, far longer than other methods. While it is very lightweight, it is relatively expensive when compared to other methods. Many hikers carry chlorine dioxide as a backup to a second primary filter or purification method, as a result. Some examples:

Ultraviolet Light Water Purification

Ultraviolet Light is an effective form of water purification that neutralizes bacteria, protozoa, and viruses. It is best used with clear water since it doesn’t remove any particulates or organic matter. While UV purification is relatively fast, it’s not good for processing large quantities of water. It also depends on working batteries, which can run out of power. Some examples:

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  1. On one of my hikes in US Southwest desert , where I do not use a filter any longer, my Aquamira Part B bottle sprang a leak and I found myself up the creek without a paddle. A few days later in a tiny town in NM I bought a small bottle of laundry bleach. Six drops per liter did the trick for the next three weeks of the hike. With this amount the swimming pool flavor was not too bad ( this may be a function of the quality/flavor of the input water, which in NM cattle country was mostly pretty gross). For those averse to the chlorine smell/flavor, addition of a small tablet of vitamin C at the end of the treatment period will solve that problem.

    It may be old-fashioned, but it’s light, cheap, does not require batteries, nor does it clog. I have heard and read contradictory information concerning the effectiveness of bleach against cryptosporidium and girardia. The opinions appeared to be held strongly and voiced forcefully without the ability to quote chapter and verse.

    • I trust the scientists on this one. Bleach is not an effective method for disinfecting Cryptosporidium and Giardia. “Disinfectants can kill most harmful or disease-causing viruses and bacteria, but are not as effective in controlling more resistant organisms, such as Cryptosporidium and Giardia parasites.”

      I use chlorine dioxide drops or a water filter and always carry a backup for my primary method, should it fail or be compromised.

  2. I have been really satisfied with my BeFree 3 liter gravity filter for several years. 3 liters is a good volume for me. What I love the most is the direct connect to my hydration system which makes it really easy to refill the bladder.

  3. Your thoughts on Rapid Pure? A virus barrier, I understand, and comes in various permutations. In its own bottle, in any wide mouthed bottle, and as a gravity filter.

    • I reviewed several of the variants last year.

      I think it really depends on your style, what type of hikes you do, and what water quality you need to protect against. The purifier functionality is only good for 25 gallons and the system is really best used with bottles. I personally prefer a large batch fill, squeeze, decant method of filtering (ie. Sawyer or Hydroblu) to using proprietary or metal bottles. But if you like carrying metal bottles, like on day hikes, the rapid pure would probably work reasonably well for you. (It’s worth mentioning that the Grayl purifier uses the same purifier/filter technology and lasts 10 times longer.)

      In New England, with the exception of Vermont (cows), water filters are usually quite sufficient and a purifier isn’t needed. But I could see using the RapidPure in Mexico or India for travel where water quality and sanitation may be suspect (if we’re ever allowed to leave the US again in a post Covid world.) For international backcountry use, I’d carry an MSR Guardian. No doubt about it,

  4. For cattle country (thinking New Mexico, Arizona) – is a purifier necessary against those pathogens, or is a filter alone sufficient? E.g. sawyer squeeze alone vs. Sawyer Squeeze + Aquamira or MSR Guardian

    • You need to consider pathogens as well as fertilizer/pesticide use. I’d certainly consider using a purifier with a charcoal component, or one of the electrostatic purifiers like a Grayl or RapidPure. If you’re hiking on public lands, your best source regarding the quality of the local water is to call the land manager (the rangers overseeing the land parcel) and asking their advice.

    • After a few thousand miles hiking through grazing country in AZ, NM, UT I have overcome my earlier water purification anxiety. Being careful about the selection of your raw water source, i.e. by careful trip planning, you can get away without a secondary treatment post filtration. I abandoned charcoal cartridges when I found that they did not lead to improved taste of marginal water. In these areas I do not worry about pesticides and fertilizer contamination as the margins in cattle ranching are so low that nobody could afford to treat the land given the size of the ranches. Downstream of human settlements I only use water from springs, potholes and seeps. For example, I would not take water from the Paria downstream of the cotton bowl by Safford or of Mineral Creek along the AZT.

      I go out for very long treks (four to eight weeks typically) and I got tired of struggling with filters in the absence of opportunities to clean them regularly. That Utah sand gets into the most ridiculous places and resists flushing. I have transitioned completely to chemical treatment. So far so good. I have learned to distribute my treatment chemicals over multiple vessels so that a leak or a spill does not force me to wing it or to bail out.

    • I suggest you take a look at the article on Desert Water Purification that Ben wrote recently. He explains how to do some of the techniques Tom describes. I’ll just say that experience matters. These guys are both pretty experienced with the terrain.

  5. Why is the First Need Deluxe purifier never mentioned? It was basically the first non chemical purifier for backpackers and had EPA backing for viruses as well as the regular nasties.

    • Because its technology, a glass fiber matrix, was superseded by newer hollow fiber filters and electrostatic purification. These newer technologies are as effective, easier for people to understand, and less expensive. The First Need was a great product. I myself used one for many years. But I switched to a Sawyer Squeeze when it first came out and never looked back.

  6. I’ve been using an Aquamira Frontier Pro Green Line cartridge with a pre-filter screwed on. I think it’s the lightest possible water filtration system there is? Mine weighs a little over 1 ounce with pre-filter and screws onto a smartwater bottle. The Aquamira Frontier Pro comes as a more bulky inline style of filter, but most of it is just plastic that isn’t critical to the function of the filter unless using it in an inline system.

    What sold me on this filter, besides the weight, is it also comes with a carbon filtering component for removing some of the chemicals. The price for the filter cartridges is steep at $15 for something that can’t be backflushed to keep using it for years and years. It’s good for a claimed 50 gallons, which equates to about $0.30 a gallon. 10 cents a gallon less than what I pay at the store, is the way I look at it in a positive light. Probably wouldn’t be ideal for thru-hikers, but works for extended trips with no resupply, especially if every person has their own filter.

    You can buy just the filter cartridge alone (Green Line filter) and use it as a standalone filter, but it doesn’t come with the pre-filter unit and felt filters. The Aquamira Frontier Pro main kit comes with the added screw-on piece for the pre-filters, along with several extra replacement filters.

    I don’t see much mention of these filter cartridges by ultra-light backpackers online. Maybe not many people realize the filter weighs less than an ounce without the pre-filter and plastic casing?

    • I used a Frontier for years before Sawyer miniaturized their purifiers and filters. I think Aqua Mira just got out marketed. I also think Sawyer’s bundling reservoirs with the filter (which is actually marketing 101 – “sell the customer a complete solution”) is still a huge benefit over the Frontier.

  7. Have you had a chance to take a look at the new Platypus Quickdraw water filter yet?

  8. I usually carry my LifeStraw personal water filter on my trips, hiking or camping. Just bring a wide-mouth bottle to refill with the water you find. Once filtered the water was delicious, completely satisfied with it.

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