How to Pick Water Filters


After checking dozens of review sites and hundreds of customer reviews - and considering our own experiences - we put together a list of stand-out water filters for backpacking. If you’re taking care of your own water, we think the Sawyer Squeeze has the speed-to-weight ratio combined with convenience at a price that works best for most folks. Got a group to care for? We like the Platypus GravityWorks, which can filter four liters in four minutes with minimal fuss. For international travel, the upgrade-pick MSR Guardian filters out viruses and cleans itself with the press of a hand-pump. Check out our full list here, or take a look at:

the full review of water filters for backpacking here

How we researched

To show off the best of the water filters for your backpacking adventures, we dove into reviews from Adventure Junkies, Backpacker, Gear Junkie, Clever Hiker, Outdoor Gear Lab, Section Hiker, and Switchback Travel. Where these professional reviews overlapped, we checked out Amazon, REI, and Backcountry customer reviews of those filters, and compared those reviews with our own experiences with them, where we could. While our personal experiences are mostly backpacking experiences, we’re confident that these filters will suit your needs whether you’re backpacking, day hiking, trail running, fishing, or taking in the sights in another country.

Photo courtesy John Carr

Photo courtesy John Carr


How to choose the best water filter for you

Turns out, there is no one-size-fits-all when it comes to water filters. To find the best water filter for you, ask yourself a few questions:

Whatcha up to? Who you doing it with?

Are you headed out for a trail run, going backpacking for a month, or traveling abroad for a year? What you’re doing - and who you’re doing it with - will go a long way to helping you decide on the perfect water filter for you. For folks filtering their own water, the Sawyer Squeeze is the most adaptable filter, able to go along on a day hike or a long-distance backpacking trip with equal ease. For fast travel or short trips outside, you might want something quick and light like the MSR Trailshot or the Katadyn BeFree; if you’re settling into international life, something less conspicuous with more hardcore filtration like the Grayl Ultralight Purifier Bottle might be best. For groups, a larger-capacity system like the Platypus GravityWorks will make life easier. Get a better understanding of each system and what might work best for your adventure here.


Where ya going?

Traveling in the US or Canada, or going farther afield? In most of North America, we’ve taken care of our sewage problems, you don’t have to worry about viruses in the water - but in other countries, that may be a different story. A filter like the Sawyer Squeeze, which has pores a tiny 0.1 microns across, is appropriate for places where there’s little risk of sewage contamination. If you’re traveling in countries where the water’s known to make visitors sick, you’ll need a usually-more-expensive solution in the form of a purifier, like the MSR Guardian, Grayl Ultralight Purifier Bottle or SteriPen Ultra, to make sure you get all the bad stuff out.

What’s your water source?

Streams, lakes, puddles, rivers, even sinks - we’ve filtered from all sorts of sources, and some filters are better at some sources than others. For example, the MSR Guardian and the Grayl Ultralight Purifier Bottle will take ickies like norovirus out of your water - but the Guardian is a bit of a bear to use in a sink, and you have to be much more careful about cross-contamination using the Grayl by the side of a stream. We talk about best applications here, so you can choose which system is right for you.


What’s your budget?  

That bottom line is important, too. Over half of the water filters in our review were around the $50 mark at time of publishing; the others ranged from the low $100s to more than $250 for extra-super-clean/safe water. You’ve got to choose the best filter for your adventure in your budget, and we’ve tried to link you to the best deals - and if you click on our links, you can have your filter and we can eat, too.  



Criteria to Consider when buying a Water Filter

Criteria to consider (aside from price):

What’s the best water filter? That’s a pretty personal question, and a pretty personal choice. While we’ve sorted out the ones we think are best for any application, below are points to ponder when you’re making your personal choice.


Sure, you need clean water - but there’s a balance between weight and convenience for everyone. Our systems range from a barely-there 2.3 ounces to a hardcore 22 ounces - but how much a system weighs often has to do with whether or not it filters out viruses. Viruses are usually found in sewage-tainted water, so they’re not a major concern in places like the US or Canada. But you might need to sacrifice on weight if you’re traveling to a place where the water is known to make people sick. Pay close attention to your needs while you’re looking at weight, to make sure you have the right tool for your adventure.

Ease of use

Trust us - you do not want to use one pressure or hand pump system to filter water for eight people. Likewise, you might not want to carry the weight of a gravity system if it’s just you by your lonesome. When choosing your water filter, think about what’s going to be easiest for you while you’re out on your adventure. Because if you get into camp and decide you’re too tired to hand pump your water through your filter (which we’ve definitely never done, not even once, why are you asking?), you’re going to have a thirsty time.


Wait time

Nothing’s instantaneous when you’re outside doing things for yourself - and water filtration isn’t any different. Still, different water filters have different wait times - the length of time you have to wait to turn that dirty water into clean water. All the water filters in our review give you a liter of clean water in 90 seconds or less, but when you’re thirsty and just gotta have that sweet sweet H2O, every second might count. So ask yourself: how patient are you, really?


At $50 or more per water filter, you’re not going to want to buy a new one every time you get a new adventuring idea. As such, you’re going to want to check on how long each filter lasts - and, if you’re choosy, the price of the filter per liter of clean water it produces over its lifetime. That price per liter ranges from $0.40 per liter all the way to less than $0.01 per liter, so you can find your own personal sweet spot. You’ll also want to think about that filter’s end-of-days. Some models have replaceable parts or filters, so you don’t have to replace the system entirely - and if that’s what you’re looking for, choose accordingly.


What it filters

Traveling in the US or Canada, things are pretty simple - all you need is a filter, and all of our reviewed models fit the bill. For example, to filter out giardia and cryptosporidium, illness-causing microbes that can be found in some US water sources, you need a filter with an absolute rating of 1 micron; all the filters we reviewed have openings that are 0.2 microns or smaller, unless they purify through UV light. If you’re traveling farther afield, though, you’ll want a water purifier, which is a filter that stops viruses, too. Viruses are smaller, so that requires a little more oomph, whether that’s in the form of a smaller filter size, electroadsorption (read: bitty electrical charge in water kills bad stuff) tech, or UV light.



Tips and water filtering tricks

Always check to make sure your water filter is working before you leave. Whether it’s a faulty UV lamp or a tear in a filter, manufacturing defects happen, and it’s best to know about them before you head out into the wilds. Many filters have a way to check on whether or not they’re working properly, and checking them before you go will help you stay happy and healthy on your adventures.

Consider carrying a backup filtration method. We don’t talk about backups in our review, but they’re a good idea. If for some reason your filter becomes inoperable, it’s best not to have to sit around your stove and boil water for the 1-3 minutes the EPA says it takes to purify it every time you want a drink. Most folks carry some form of backup chemical purifier, like iodine tablets or chlorine dioxide droplets. We’ll talk more in-depth about these purification methods in another review.


Looks gross? Consider pre-filtering. That water source that has a lot of dirt/leaves/bugs in it? All that extra junk is probably going to clog your filter, making it less efficient at best, or less effective at worse. If you carry something like a bandana, coffee filter, or Dollar Store pantyhose as a pre-filter, and pull all your water through the pre-filter before you filter it, you’ll keep your filter cleaner and keep that crap out of your water to boot.

Gross taste? Consider adding some sort of flavoring. Plenty of outdoorspeople carry Gatorade powder for electrolytes, but other water-flavoring goodies, like Mio or fruity teas, can take the edge out of a particularly gross-tasting batch of water. If it’s your bottles or filter that tastes gross - usually like plastic - run some tap water with either lemon or lime juice through them before heading out. That should diminish that distasteful flavor.

Collecting water from a shallow spring.jpg

Drops and freezing temperatures are not your friends. Each of these water filters is a delicate piece of equipment, and care needs to be taken to make sure they continue to work. Most of these filters have a hard time surviving falls, and water expanding into ice at freezing temperatures can also break them. The worst part? Without taking extra time to test them after an incident, you may not be able to tell that it’s broken. Take special care to keep your filters secure, and if you know you’re camping at temps below freezing, consider sleeping with your water filter in your sleeping bag (double bagging it in a zip bag will keep you dry). Better safe than sorry.

Collecting from stillwater with a collapsible bag? Patience is key. If you’re using the plastic collection bags that come with the Sawyer Squeeze, or hydration bladders like the Platypus or Evernew, you’ll need technique to collect from lakes and other still water sources. Wrap your hand around the opening, and gently blow through your hand into the bag to inflate it, allowing room for the water to enter while keeping contaminants away from your mouth. Then, skim your bag across the surface of the water until it gets enough weight in it to sink, which should let you collect more easily. If you know you’re going to be in an area where you’ll have to collect from shallow puddles, fashion a scoop by cutting the bottom third off a Sawyer bag or even a Gatorade bottle. Then, just scoop the water into your dirty container for filtering.


Traveling internationally? Get a purifier. We know, we know, we’ve mentioned it a bunch, and purifiers are more expensive - but if you use your run-of-the-mill water filter in countries where the sewage systems aren’t the best, you’ll still potentially be exposing yourself to viruses. Numerous waterborne viruses cause the stomach flu, which can knock you out of commission for days at a time - so drop that extra cash and make sure you’re covered.

Beware cross-contamination. Make sure you remember which bottles or bags are dirty and which are clean. Most systems have built-in reminders, but being extra-cautious never hurts. If you dip the bottle you drink from into a water source, make sure you rinse it with clean water before drinking. You wouldn’t want to filter and then have leftover nasties still waiting for you on your bottle’s lip.

Want to worry less about clean or dirty water sources? Practice Leave No Trace. Many of the Seven Principles of Leave No Trace have to do with protecting water sources. One of the biggest sources of contamination? Fecal material. (Gross.) Make sure you’re doing your business at least 200 feet from water (and camps and trails, for that matter), and do your washing away from water for good measure, too.

Clean it before you store it. Most filters have a recommended method of cleaning. Usually, it involves running a watered-down bleach solution through the filter and drying it thoroughly before storing it. The last thing you want is to get ready for your next trip and find that mold’s grown in your filter (which has definitely never happened to us, not even once, so many questions, why are you asking). Take care of your equipment, and it can better take care of you.


Curious about what backpacking water filters made our list? 

Read Treeline Review’s Best Backpacking Water Filters of 2018 full comparative review here or check out the comparison chart.


Our Picks