Gear

Drink Up: 7 Best Backpacking Water Filters to Keep You Hydrated

by Mac Misseldine

backpacking water filters
Photo: Martin Jernberg

When you’re trekking through the backcountry on a multi-day adventure, finding clean drinking water can be challenging.

Unfortunately, fresh water in the wild if far from fresh. In addition to environmental particulates like mud, silt, sediment, and leaf debris, the water you find in lakes, ponds, rivers, and streams could be teeming with giardia, cryptosporidium, salmonella, E. coli, and more.

Rather than roll the dice at intestinal roulette, plan ahead and pack a water filter to remove harmful bacteria and parasites from water sources. Even better, consider upgrading to a water purifier that can eradicate all microscopic threats, including viruses, lurking in the water.

Buyer’s Guide

Remember learning about bacteria, protozoa (aka parasites), and viruses in freshman biology? It turns out those lectures you slept through have a practical application for backpackers.

When humans, wildlife, and livestock come in contact with a body of water, their waste deposits harmful bacteria, parasites, and sometimes viruses in the water. The greater the local population, the higher the content becomes.

Animals are better equipped to stomach these threats, but humans are unfortunately quite susceptible. When a backpacker comes along and drinks tainted water, the bacteria and protozoa in the water can wreak havoc on their gastrointestinal system. When there’s a virus lurking in the water you’re drinking, the effects on your body can be far more serious.

In the old days, the best way to kill these microscopic hitchhikers was to boil your water. That’s still an option today, but fortunately technology has evolved to make filtering and purifying your water faster, easier, and more effective.

How To Find And Filter Water In The Backcountry

It’s important to plan where you’ll obtain water for drinking and cooking before embarking on your adventure. Packing water in a hydration bladder or water bottle is fine for day hikes, but you’ll find yourself grossly unprepared and overladen should you attempt to pack all your water in advance for a multi-day backpacking trip.

The good news is that in most areas, mother nature provides plenty of sources to obtain fresh water. The trick is to grab a map and plan your hike around these natural sources, then pack the proper gear to filter the water for drinking and cooking.

find water in backcountry
Photo: Jon Cartagena

Of course, not all freshwater you’ll find in nature needs to be filtered. The groundwater you draw from lakes, ponds, rivers, and streams should be filtered for bacteria and protozoa, but rainwater and snow are naturally pure and safe to consume provided they’re collected in sterile containers.

You can also collect clean drinking water from morning dew, plant transpiration, fruits and vegetation, and underground stills, though these are beyond the scope of our conversation today. Check out this article from The Art of Manliness if you’re curious about how to find water when surviving in the wilderness.

The Difference Between A Filter And A Purifier

While they generally accomplish the same purpose of providing clean drinking water, there’s a key difference between filters and purifiers. Water filters — the more popular and affordable choice — physically remove protozoa (parasites) and bacteria with a strainer.

Water purifiers, on the other hand, are able to eliminate protozoa, bacteria, and viruses that are too small for filters to catch. Some water purifiers accomplish this with a more advanced strainer, while others rely on ultraviolet rays or chemicals.

Why is this important? Water-borne viruses aren’t a major concern in the United States, but they’re a huge problem in developing countries where local populations dump human waste and trash into local water sources. While carrying a simple water filter to remove protozoa and bacteria should be sufficient for backpacking trips in the United States and Canada, you’ll need to use a water purifier on international adventures to eliminate viruses.

Of course, it doesn’t hurt to be extra cautious and use a water purifier when backpacking in the United States. Water-borne viruses are rare here, but the risk goes up when the local population spikes over a holiday weekend. When you’re drawing water from a popular watering hole, consider using a purifier tablet or UV pen after filtering your water for the best level of protection.

Types Of Water Filters

There are a number of ways you can filter water in the backcountry. Each type of filter has a unique set of strengths and weaknesses, including ease of use, volume, weight, and side effects.

Gravity Filters

Why strain your arms when gravity can do the work? A gravity filter typically involves hanging a reservoir of unfiltered water higher than an empty reservoir, and allowing the water to naturally proceed through the filter into the clean reservoir. This filtration method is easy to use and can handle large volumes, so it’s ideal for use in group settings.

Pump Filters

As the name implies, pump filters require some manual labor to clean your water. Place the receiving end of the hose in the water, position the filter over the receptacle (water bottle, hydration bladder, etc.), then pump the water through by hand. This filtration method is extremely reliable and can process large amounts of water, though it can be tiring. Pumps are also among heaviest types of filtration systems.

Bottle Filters

There are many types of bottle filters, but the idea is the same. Whether the bottle filters water as you drink, requires a pressing action, or utilizes UV rays, this is the easiest and most convenient form of water filtration for solo backpackers.

Squeeze Filters

Squeeze filters are fairly intuitive — just fill the pouch, attach the filter, then force the water in the pouch through the filter by squeezing. You can squeeze it directly into your mouth, into your water bottle, or into a hydration bladder. This form of filtration is fast, easy, and ultralight, though the replaceable filters don’t last as long.

Straw Filters

A favorite of ultralight backpackers, straw filters let you sip water straight from the source. It’s fast, easy, and ultralight, but it only works when you’re at the source of water (i.e. you won’t be able to fill up your bottle or hydration bladder). These are great in wet regions where water sources are very common, but are not so practical where water is more scarce.

UV Purifier

Sometimes referred to as a UV pen, UV purifiers use ultraviolet rays to kill the bacteria, protozoa, and viruses in water. They’re easy to use, incredibly fast, and low-maintenance, often requiring just a minute of stirring water with the UV pen. Just don’t forget the batteries!

Chemical Tablets

If you’re looking for the easiest, lightest option to completely purify water, this is it. Simply add a chemical tablet, wait the prescribed time (usually 30 minutes to four hours), and you’re good to go. They’re inexpensive and an excellent backup measure when used with another type of filtration, though chemical tablets sometimes impart a bitter taste.

Iodine products aren’t effective against cryptosporidium, and they’re not recommended with pregnant women or individuals with a thyroid condition, so you’ll need to exercise caution when using them. Tablets also leave a weird taste in the water that is off-putting to some users.

Special Considerations For Backpackers

When selecting a water filter for backpacking, there are a few special considerations to keep in mind:

  • Portability: it goes without saying that weight and size are critical when you’re dealing with limited space in a backpack. You’ll have to strike a balance between weight, size, and functionality.
  • Capacity: certain types of filters are better equipped for backpacking parties, while others are ideally suited for solo backpackers. Capacity also plays a critical role when you’re backpacking through an area with limited water sources, as you may need a larger reservoir to sustain you for a day or longer between fill-ups.
  • Field Cleaning: when you’re dealing with dirty water, particles like mud, silt, sediment, and leaf debris can quickly clog up a filter. You’ll either need to choose a filter that’s easy to clean in the field (usually though backflushing), or select a purifier that doesn’t require cleaning (like chemical tablets or UV pens).

Our Picks for the Best Water Filters

The ultimate decision as to which type of filter is best for you comes down to your personal style and preference. Where you’ll be backpacking should factor into your decision, too, as the local environment will dictate how much freshwater is available, and what microscopic threats you’ll need to watch out for.

We’ve compiled an eclectic list of the best backpacking water filters. There’s an option for everyone, whether you’re a fan of pump filters, gravity filters, squeeze filters, bottles, or straws. We also included a premium water purifier for international backpackers who need to eradicate viruses from water sources.

All of these have been successfully field tested and are backed by strong reviews from the backpacking community, so you can trust they have what it takes to keep you safely hydrated on backpacking adventures for years to come.

Best Pump Filter: MSR MiniWorks EX Water Filter

MSR MiniWorks EX Water Filter

The MSR MiniWorks EX Water Filter is the most popular water filter on the market, successfully field tested by thousands of backpackers around the world. It’s lightweight, dependable, easy to clean, and extraordinarily effective.

The secret to the MSR MiniWorks is the ceramic/carbon Marathon EX filter element that effectively removes bacteria and protozoa. The top-rated filter even removes unpleasant tastes and odors caused by organic compounds like pesticides, chlorine, and iodine, resulting in more pleasant, refreshing drinking water. The AirSpring Accumulator boosts filtration speed, so the filter accomplishes more in less time to get you back on the trail faster.

The MSR MiniWorks EX Water Filter is easy to disassemble, clean, and maintain without any tools, so it’s a piece of cake to troubleshoot in the field. The pump is specifically designed for use with an MSR Dromedary Bag and Nalgene water bottles, but it can be adapted to work with most third-party hydration bladders and water bottles.

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Tech Specs

  • Filter Type – Pump
  • Filter Medium – Ceramic with carbon core
  • Removes – Bacteria, protozoa
  • Output – 1 liter per minute
  • Field Cleanable – Yes
  • Dimensions – 7.8” x 3.8”
  • Weight – 14.6 ounces

Best Gravity Filter: Platypus GravityWorks Water Filter System

Platypus GravityWorks Water Filter System

The Platypus GravityWorks Water Filter System delivers the speed and utility of the original Platypus CleanStream in an upgraded design that’s lighter and more durable. It produces four liters of potable water in just over two minutes with no pumping required (sigh of relief from your exhausted arms). Even better, the four-liter reservoir lets you keep a large supply of clean water in your campsite, eliminating unnecessary trips to the nearest water source.

Operating the Platypus GravityWorks Water Filter System couldn’t be easier. Just fill the unfiltered-water reservoir with water, hang it above the clean-water reservoir, and let gravity carry the water through the filter.

The hollow fiber filter technology boasts a flow rate of 1.75 liters per minute, and effectively removes particles, protozoa, and bacteria down to 0.2 microns. When you’re done, perform a simple field clean by holding the clean-water reservoir above the unfiltered-water reservoir to backflush the filter.

The Platypus GravityWorks Water Filter System comes with two four-liter reservoirs with hang loops, both coated in a SlimeGuard antimicrobial treatment for taste-free performance. The unfiltered-water reservoir features a quick-disconnect valve that automatically stops the water flow when the hose is disconnected, and the shut-off hose clamp on the clean-water reservoir hose makes it easy to control the outward flow for filling up water bottles.

Each microfilter is good for up to 1500 liters, or 375 complete fill-ups with the four-liter reservoir.

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Tech Specs

  • Filter Type – Gravity
  • Filter Medium – Hollow fiber
  • Removes – Bacteria, protozoa
  • Output – 1.75 liters per minute
  • Field Cleanable – Yes
  • Dimensions – 17.7” x 9.1” reservoir, 2” x 8.5” filter
  • Weight – 11.5 ounces

Best Bottle Filter: Grayl Ultralight Water Purifier Bottle

Grayl Ultralight Water Purifier Bottle

Why pack a water bottle and a filter when you can save weight with a 2-in-1 solution? With the push of a button, the Grayl Ultralight Water Purifier Bottle converts any freshwater source into clean drinking water in 15 seconds. It’s fast, powerful, and easy to use, whether you’re drawing water from a lake, stream, tap, or hotel sink. When you’re not on the trail, try bringing the Grayl Ultralight Water Purifier Bottle on road trips to avoid wasting money on plastic water bottles.

The Grayl Ultralight Water Purifier Bottle removes over 99.9% of viruses (Rotavirus, SARS, Hep A), bacteria (salmonella, E. coli), and protozoa (cryptosporidium, giardia). The filter meets NSF 42 and 53 standards, and features a secondary filter with ultra-powdered activated carbon to remove particulates, chemicals, and heavy metals, to effectively eliminate odors and unpleasant taste.

While the bottle itself has an indefinite lifespan, you’ll need to replace the filter every 300 uses. The bottle conveniently fits in most cupholders and backpack pockets, and is engineered to withstand heavy use and abuse outdoors.

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Tech Specs

  • Filter Type – Press, bottle
  • Filter Medium – Electro adsorption and activated carbon
  • Removes – Bacteria, viruses, protozoa
  • Output – 2 liters per minute
  • Field Cleanable – No
  • Dimensions – 9.5” x 2.7” x 2.7”
  • Weight – 10.9 ounces

Best Squeeze Filter: Sawyer Squeeze Water Filter System

Sawyer Squeeze Water Filter System

Ultralight gear tends to be more expensive, but in this case the lightest backpacking water filter is also the least expensive. It’s also the easiest to use — simply fill up the water pouch, screw on the hollow-fiber filter, and then squeeze the pouch to force the water through the filter into your mouth. No pills, pumps, or wait time required.

The Sawyer Squeeze Water Filter System uses a hollow-fiber membrane filter to remove over 99.9% of protozoa and bacteria, including giardia, cryptosporidium, E. Coli, cholera, and salmonella.

The filter’s collapsible pouches are constructed with durable Mylar foil that can be reused hundreds of times, and the kit includes a syringe you can use to backflush the filter with clean water to maintain an optimal flow rate.

The Sawyer Squeeze Water Filter System is surprisingly versatile. Should you prefer to filter water into a water bottle instead of directly squeezing into your mouth, the filter threads onto most commercially available water bottles you can get at the grocery store.

The kit also includes inline adapters for use with a hydration pack, and gravity tubing to hook up the Squeeze Filter as a gravity filter.

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Tech Specs

  • Filter Type – Squeeze, gravity
  • Filter Medium – Hollow fiber membrane
  • Removes – Bacteria, protozoa
  • Output – 1.7 liters per minute
  • Field Cleanable – Yes
  • Dimensions – 11” x 6” squeeze pouch, 5” x 2” filter
  • Weight – 3 ounces

Best Straw Filter: LifeStraw Flex

LifeStraw Flex

Ultralight backpackers seeking a versatile water filter will love the LifeStraw Flex. The 4-in-1 water filter can be used independently as a personal straw, in conjunction with a hydration bladder, attached to a plastic water bottle, or as a gravity filter with the included one-gallon gravity bag.

Should you choose the latter route, the one-gallon gravity bag lets you keep a large supply of clean drinking water in your campsite or in your backpack for easy access.

The LifeStraw Flex uses a two-stage filter to remove over 99.9% of bacteria, parasites, and microplastics, exceeding US EPA drinking water standards for bacteria and parasites. The filter reduces organic chemical matter like VOCs, herbicides, and pesticides, exceeds NSF 53 standards for reduction of lead and heavy metals, and surpasses NSF 42 standards for chlorine reduction.

The filter offers an extended lifetime with the ability to handle up to 2,000 liters, and each carbon capsule lasts up to 100 liters.

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Tech Specs

  • Filter Type – Gravity
  • Filter Medium – Hollow fiber membrane with activated carbon
  • Removes – Bacteria, protozoa
  • Output – 0.5 liters per minute
  • Field Cleanable – Yes
  • Dimensions – 11” x 5.4” x 2.6”
  • Weight – 5.7 ounces

Katadyn Hiker Microfilter

Katadyn Hiker Microfilter

For a lighter, more affordable pump filter, check out the Katadyn Hiker Microfilter. This easy-to-use pump filter physically removes particles, bacteria, and protozoa down to 0.2 microns in size, and features an activated carbon core that absorbs pesticides and chemicals to improve the taste of your drinking water.

There’s a pre-filter located at the hose inlet that filters to 150 microns, effectively removing larger contaminants before they reach the filter to increase the product’s lifetime. The filter uses a pleated glass-fiber element to maximize surface area and more-effectively handle muddy water and silt.

The Katadyn Hiker Microfilter comes with a bottle adapter that fits most water bottles, and a bladder adapter that attaches to the quick-connect fitting built into some hydration reservoirs. The kit also includes a carry sack to keep everything organized when you’re on the trail.

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Tech Specs

  • Filter Type – Pump
  • Filter Medium – Pleated 0.2 micron fiberglass and carbon core
  • Removes / Destroys – Bacteria, protozoa
  • Output – 1 liter per minute
  • Field Cleanable – No
  • Dimensions – 6.5” x 3” x 2.4”
  • Weight – 11 ounces

Best Water Filter + Purifier: MSR Guardian Purifier

MSR Guardian Purifier

The award-winning MSR Guardian Purifier carries a premium price tag, but it’s worth every penny. In addition to removing dirt, bacteria, and protozoa like all of the other filters we’ve discussed, the MSR Guardian Purifier also blocks viruses — a feat that your average hollow fiber filter can’t replicate. That may not be a major concern when you’re backpacking in the United States, but it’s a critical feature on international backpacking adventures with poor local water sources.

The secret to the MSR Guardian’s success is an advanced hollow fiber filter with medical-grade fibers, capable of removing bacteria, viruses, particulates, and protozoa from fresh water. It’s able to purify 2.5 liters per minute (more than twice the average output), and it features a self-cleaning function that eliminates the need for manual backflushing.

On the outside, the MSR Guardian Purifier’s rugged shell can absorb drops up to six feet and withstand freezing temperatures.

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Tech Specs

  • Filter Type – Pump
  • Filter Medium – Advanced hollow fibers
  • Removes / Destroys – Bacteria, viruses, protozoa
  • Output – 2.5 liters per minute
  • Field Cleanable – Yes
  • Dimensions – 8.2” x 4.7” x 3.5”
  • Weight – 17.3 ounces

Gearing up for a big backpacking trip? We’ve got a crap-ton of backpacking buyer’s guides at your disposal. Need a tent that won’t break the bank? Here’s our fave backpacking tents under $100. How about a new headlamp? We’ve even picked out best best backpacking chairs so you can stay comfortable at camp, if you’re into that sort of thing.

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