A backpacking water filter is a key essential for any multi-day outdoor adventure. Why is a water filter so important? Parasites and viruses live in the lakes and rivers that you rely on to stay hydrated. Giardia is the most common and can cause abdominal cramping, nausea, diarrhea, and vomiting – not exactly what you had planned for your next adventure, right? Some argue you don’t always need to filter where streams are fed by fresh snow-melt, but keep in mind if livestock, wildlife or humans can reach an area, so can contaminants which are transferred via fecal matter.
Kristen’s got the John Muir Trail under her belt, and Kim (Bearfoot Theory’s new editor) conquered the Pacific Crest Trail this past summer. So between us, we have easily filtered more than 1,000 liters of water in the backcountry. We’ll walk you through the important factors to consider when choosing a backpacking water filter and leave you with our favorite recommendations for your next adventure, whether it’s a quick weekend backpacking trip, a car camping expedition or a long distance thru-hike!
Be wise in selecting a backpacking water filter so you stay hydrated and enjoy more time outside exploring our nation’s great outdoors. Photo Cred: Tyler Cosgrove
••• The Most Important Factors In Choosing A Backpacking Water Filter •••
Purification vs. Filtration
Let’s start here, it’s important to know the difference! The difference between a water filter and a water purifier is the size of the microorganism each fight. Purification eliminates viruses while filtration removes bacteria. Bacteria in water sources is a concern within the USA and Canada, while protection from waterborne viruses is more important for international travel. Filtration also removes debris and silt making the water more pleasant to drink, while purification does not.
Weight of Backpacking Water Filter
Weight is an important factor to consider for all of your gear, and water filters are no exception, especially on a long-distance trip. While not always the case, there tends to be a tradeoff between weight and speed of filtering. The smaller and lighter the filter, generally the longer the filtration process.
Speed of Backpacking Water Filter
How patient are you? Some filters are speedy, while others take quite a bit of your limited time in the backcountry. It is also important to consider how many people you will potentially be filtering water for, since more people means more time. Using chemicals, such as chlorine or iodine, to purify water can take up to 4 hours while other filters can immediately do the job within minutes. If you are on any kind of backpacking trip, whether just a quick weekend trip or a thru-hike of a long distance trail, time is of the essence–remember you came to explore the outdoors, and you will not want a treatment method that takes a long time!
Filtering water takes time! It’s important to keep in mind the length of time different filters require and how often you’ll need to filter water. Photo taken in the Marble Mountains Wilderness along the PCT. Photo Cred: Sour Patch
Type of Backpacking Water Filter
Some filters require simple set-up and then allow you to sit back and relax while your water is filtered. For example, gravity filters work by using gravity to filter water from one bag to another. Other filters require active participation–meaning you have to physically filter the water usually by either squeezing or pumping. It is important to also consider that some backpacking water filters are ceramic and cannot be exposed to extreme cold temperatures.
How clear is your source?
Different elements can murk up water in varying ways, such as glacial sediment, leaf debris and/or mud stirred up by a recent rainstorm. If you plan to use a SteriPEN or chemicals you’ll need to bring something to act as a filter to help you remove dirt and debris prior to filtering. Depending on how congested the water is sometimes a simple bandana can act as a pre-filter.
Only some filters can take on as tough of jobs as this! Photo Cred: Sarah Delgado Parry
••• The Best Backpacking Water Filters •••
These are some of the most popular backpacking water filters available. These water filters are listed in order of weight starting with the lightest option.
— Potable Aqua or Aquamira Tablets/Drops —
Weight: Varies (0.9 oz – 6 oz)
With water purification tablets or drops it’s 3 simple steps: 1) collect water, 2) add purification tablets or drops, and 3) wait. Generally you have to wait before consuming the water for anywhere from 30 minutes to 4 hours. Keep in mind drops and tablets only work well for clear water sources, and you also have to make a personal decision about the chemicals you ingest using these tablets.
Great For: weekend backpacking trips, back-up water purification method, car emergency kit, natural disaster home preparation kit
— Katadyn BeFree Collapsible Water Filter Bottle —
Weight: 2.3 oz.
Having won the Runner’s World “Gear of the Year Award,” we definitely want to give a nod to this great lightweight option. Filtering 1 liter of water per minute, it’s pretty speedy for a short weekend trip or quick trail run. The filter sits inside the water bottle, so all you do is fill it up, and as you drink the water gets sucked up through the filter. The bottle is collapsible when it’s empty, making for easy packing in any size pack or you can even carry it on a hip belt!
Great For: trail runs, hiking where water is abundantly available.
— Sawyer Mini —
Weight: 2 oz.
The Sawyer Mini is the lightest in the Sawyer family of water filtration products, weighing in at 2 ounces. The Sawyer Mini does take a substantial amount of time to filter multiple liters and needs to be back flushed much more often than other filters. Back flushing is how you clean the filter, this is done by using a syringe to shoot water through the filter in the opposite direction that water filtration generally takes place. You can use the Sawyer Mini to drink directly from a stream or you can stick it in a whatever water bottle you want and start sipping through the top of the filter. Kim started the PCT with this water filter option but quickly upgraded to the Sawyer Squeeze after only 1 month.
Great For: trail runs, day hikes, solo weekend trips
— Sawyer Squeeze —
Weight: 3 oz.
Awesome and lightweight but requires a little manual power – which was the only con Kim found with this product while using it for 4 months on the PCT. The Squeeze can also be rigged into a neat do-it-yourself gravity filter! The Sawyer squeeze works by filoing up the included water pouch in a lake or stream, screw on the filter to the top, and then squeeze the pouch to push water through the filter and into your mouth. The filter inside the Sawyer Squeeze is ceramic which means it can freeze. A quick fix to prevent this is to put it with you in your sleeping bag at night.
Great For: multi-person weekend trips (each person has their own), long distance hiking
— SteriPEN Ultra —
Weight: 4.8 oz.
The SteriPEN uses ultraviolet rays to purify up to 32 oz in 90 seconds. It is great, as long as your water source is clear and free of debris! SteriPENs are especially good for international travel. To purify water with a SteriPEN, you fill up your water bottle, swirl the SteriPEN around for 90 seconds, and the water is ready to drink. During Kristen’s Anywhere Plus trek in Nepal, her guide had 2 SteriPENs and was able to quickly purify water for the entire group of 11 people during breakfast. The SteriPEN classic takes batteries, while the SteriPEN Ultra is rechargeable with a USB cord, so it can run off an external battery charger or a solar panel! SteriPEN also makes an option that is an ounce lighter, called the Adventurer but it requires lithium batteries which can be expensive ,and you’ll need to carry back-up batteries to be safe!
Great For: international travel
Sit back and enjoy the view while using the SteriPEN, shown here on the PCT purifying water while also collecting solar charge! Photo Cred: Christina Fawn
— MSR 2L AutoFlow Gravity Filter —
Weight: 10.5 oz.
If Kim was to ever long distance thru hike again she swears she’d upgrade to a gravity filter! Having a snack while sitting back and letting your water filter itself sounds awesome! Gravity filters filter water by using gravity–there is no squeeze or pumping necessary! They generally have two bags that are connected by a long tube with a filter. One bag is designated for dirty water, which you fill with your water source. You then hang that dirty bag, and gravity carries water down through the filter and into a new container. The MSR Gravity Filter can filter 1.75 liters per minute. The great thing about the MSR model is it only includes one 4L bag, which you can use to filter water into any container you’d like, such as a Nalgene, CamelBak, reservoir bag, cooking pot, etc.
Good For: big groups, setting up a fixed campsite in the backcountry for a few days, or car camping where there is no potable water available
— Platypus 2L GravityWorks Filter —
Weight: 11.5 oz.
Similar to the MSR model, Platypus has a great option as well. The Platypus system includes a both a 2L dirty water collection reservoir as well as a 2L Platy reservoir for clean filtered water. Check out our awesome detailed review and video of the Platypus 2L Gravity Filter when Kristen used it in Zion National Park! This is also the filter Kristen used on the John Muir Trail, although she only used the dirty bag and filtered it into a super lightweight Platypus Soft Bottle.
Good for: big groups, setting up a fixed campsite in the backcountry for a few days, or car camping where there is no potable water available
Looking for a bigger option? Snag the Platypus 4L system for group or family trips into the backcountry!
Gravity filters give you the great ability to sit back and relax while your water filters! Keep in mind though they can be difficult to use in the desert where you might not be able to find a source to elevate one bag–cactuses are not recommended for that!
— MSR MiniWorks EX Water Filter —
Weight: 14.6 oz.
This great hand pump filter has a ceramic/carbon filter to removes bacteria and filters water at 1 liter per minute. The bottom can also easily screw onto a Nalgene for easy operation.
Good for: setting up a fixed campsite in the backcountry for a few days, car camping
Disclosure: The links in this post are affiliate links which means if you make a purchase, I receive a tiny bit of compensation at no added cost to you. Any purchases you make help keep this blog going…so thanks for all of your support! If you ever have any questions about any of the products featured on my site, please email me. Thanks! Kristen