When you’re hiking the backcountry, few things are more enticing than a drink from a pristine mountain stream. Unfortunately, it’s impossible to know what sort of microorganisms might be lurking in that crystal-clear water. Giardia, amoebas, and samonella are often present in streams, and any one of them can bring your journey through the wilderness to an abrupt end – and put you in what seems like a permanent position on the toilet.
| Filter | Price | Our Rating | |
|---|---|---|---|
| Katadyn Vario |  | REI / Amazon | A+ |
| Sawyer Mini Water Filtration System |  | REI / Amazon | B |
| MSR Guardian Purifier Pump |  | REI / Amazon | A |
| Grayl Ultralight Water Purifier |  | REI / Amazon | C |
| Lifestraw Personal Water Filter |  | REI / Amazon | B |
While some mountain streams are safe to drink from, it’s best not to gamble on your GI tract, especially when you’re in the backcountry. Fortunately, most water filters are relatively inexpensive and easy to use, and the peace of mind that comes with knowing you’re safe from waterborne disease is invaluable.
Water Purification
The best water filter for you will be determined by where and how you want to use it. If you’re drinking from a pure mountain stream, you won’t need to be as concerned about filter quality and will want something that puts you back on the trail as quickly as possible. Sourcing your water from a lake surrounded by high-traffic trails, on the other hand, requires a more robust filter. These are some of the features you’ll need to consider when choosing a water filter.
Filter Quality
Every filter on the market will take care of some amount of the pollutants in your water, but it’s a question of how much. Most filters can remove bacteria and protozoans, the most common microorganisms found in backcountry streams. To do this, the filter forces water through very small pores (usually 0.2 microns across) that the microorganisms cannot fit through. But few filters will remove viruses, which are much smaller and will go right through the pores. Fortunately, this isn’t much of a problem in developed countries. You should be cautious whenever you’re hiking popular trails where contamination with human feces is possible, though.
In developing countries where waterborne viruses like hepatitis A and polio are present, it’s best to use a chlorine-based disinfectant instead of a filter (or in addition). However, neither filtering nor chlorine will remove heavy metals like lead, mercury, cadmium, or chemicals, so water sources containing these pollutants should be avoided altogether.
Size and Weight
When you’re talking about your health and safety, the amount of weight your filter can add to your pack might seem trivial. But for those who will be hiking long distances with it, every ounce counts.
Water filters fall into two main categories: pump-action and suction. Pump-action filters take up considerably more space because, in addition to the filter, they also have a pumping mechanism and one or two hoses. They’re best for hikers who need to filter large quantities of water, as they are quicker to operate.
Suction filters are meant to fit on top of a water bottle or are integrated into a straw. The force to operate them comes from the user sucking the water through the filter. They take up much less space and weigh about a fifth of their pump-action counterparts. They’re a better choice if you need to cut down on weight or don’t see yourself using the filter very often.
Ease of Use
If you won’t be using the filter too often, like if you’re only carrying one in case of an emergency, ease of use is less of a concern. But if you hike every weekend during the summer and need to filter a few liters of water every time, you’ll definitely need something that’s easy to use.
Pump-action filters can be more convenient in that they clean large amounts of water quickly and with minimal effort. The downside is that they require preparation and cleaning: unpacking, connecting hoses, cleaning the prefilter after pumping silt-filled water, and putting everything away. But once you get some experience with them, pump-action filters a cinch, and you’ll have your hiking group loaded up with water in just a few minutes.
Suction filters are easy to use in that they only require you to connect the filter to a water bottle or dip it in the source. Once set up, they are more difficult to use than their pump-action counterparts, though. Sucking even a small amount of water through the filter can take some effort, and there’s no easy way to filter for an entire group. Each member of your hiking party will need to have their own filter if you’re using this type.
Longevity and Durability
If you see yourself using a water filter more than a couple times each year, you’ll need to consider replacement filters as well. Replacing the main filter cartridge in a pump-action filter usually costs about half of what you paid for the filtration system. Suction-style filters are not replaceable per se, because the filter itself makes up almost the entire system.
You’ll also need to look into whether the filter can be cleaned in the field to prevent it from clogging. A water filter might be rated to clean 2,000 liters of water before it needs replacing, but a silt-filled stream can clog it in just a few liters, meaning you’ll need an easy way to clean it during your trip.
Lastly, and be honest with yourself on this one, how conscientiousness are you with your gear? Do you drop things often? If so, choose a filter that won’t crack when it slips through your “butter fingers.” Do you often hike in cold climates? Many filters cannot be exposed to freezing temperatures and will need to be stored in your sleeping bag at night. More durable filters usually come with a higher price tag, but that’s nothing if it will prevent you from being stranded in the backcountry without clean water because your filter broke.
Five of the Best Backpacking Water Filters
Katadyn Vario Water Filter
The Katadyn Vario might be one of the best mid-grade water filters on the market today. It can pump two liters of water per minute, fast enough to quickly clean enough water for your entire hiking party, and it comes with a total of three filtration systems to provide some of the cleanest water of any of the filters on this list.
When using the Vario, water first passes through a ceramic filter, which will catch any sediment and prevent it from clogging up the main filter. From there, it goes through a glass fiber filter that removes harmful bacteria and protozoa. As a final step, an activated charcoal core removes chemicals like chlorine and pesticides. The charcoal won’t make toxic sludge clean, but it can remove some noxious tastes and smells from the water. Be aware, though, that it does not remove viruses.
The Vario does have a few downsides though: while the ceramic filter can be cleaned in the field with the included scouring pad, once the glass filter cartridge is clogged, there’s not much that can be done except replace the cartridge (it has a 2,000-liter lifespan). The Vario also weighs almost 20 ounces and takes up as much space as a one-liter water bottle. There’s also the problem of the pumping mechanism having the tendency to occasionally “air lock,” or completely seize up. When this happens, you’ll need to disassemble the filter and pump it to get the air bubble out.
Despite these drawbacks, the Vario is a well-rounded filter that could be a great option if you need something that can rapidly filter large amounts of water and you’re not worried about a little extra bulk.
Pros:
- Ceramic prefilter prevents clogging
- Carbon core removes some toxic chemicals
- Fast pumping action
Cons:
- Not very compact or lightweight
- Replacement filter cartridges are expensive
- Can become “air locked”
Sawyer Products Mini Water Filtration System
Sawyer has been making some incredibly innovative (and inexpensive) products in the past few years, providing much-needed alternatives to the stagnant market of pump-based filtration systems. There’s no pumping or sucking with the Mini, though. Instead, you attach a water bladder to the filter system and then squeeze it to push water through the hollow fiber filter and into your water bottle. It’s a simple design that cuts down on weight (it weighs two ounces), bulk (the filter is only five inches long and one inch wide), and price (it’s a third the price of most pump filters).
That doesn’t mean the Mini is without problems, though. It has no prefilter, so sediment will clog the fibers if you’re not careful. Filling up the bladder is a challenge in itself, requiring several scoops in your water source, but it’s something you get used to with time. Many users have also reported that the seals leak, but this can be remedied by carrying an extra set of O-rings.
Overall, the Sawyer Mini is a great product for those who need an inexpensive, compact water filter and are okay with a little bit of a learning curve.
Pros:
- Compact design
- Very inexpensive
- Can filter quickly
Cons:
- Clogs fast
- Hard to use
- Prone to leakage
MSR Guardian Purifier Pump
Sometimes you need a filter that can do it all. Maybe you’re working in a developing country where there are more viruses in the water, or you want a back-up water purification system in case a natural disaster strikes. Either way, you need more than what most backcountry water filters are capable of – you need the MSR Guardian.
The pump-action Guardian takes purification to a whole new level by filtering out viruses (.02 micron filtration) in addition to protozoa and bacteria. This is a necessity if you’ll be pulling your water from a contaminated source near a population center.
The Guardian is also capable of filtering 2,000 liters before the filter cartridge needs replacing, making it ideal for large groups. It was designed to military specifications, which means it can withstand a few drops and won’t crack if it gets frozen. The filter never needs cleaning as the pumping mechanism is designed to “wash” the filter on every stroke.
Not surprisingly, the downside to the Guardian is that all those features and bulletproof design come with a very high price tag and an extra few ounces. It also has no prefilter, so silty water can still clog the filter if you’re not careful.
Pros:
- One of the only filters that removes viruses
- Self-cleaning
- Incredibly durable
Cons:
- Very expensive
- Heavy
- Has no prefilter, silty water will clog it
Grayl Ultralight Water Purifier
Most of the camping water filters in use today rely on a simple principle: forcing water through very small holes that pollutants are too large to travel through. The problem with this concept is that viruses, chemicals, and heavy metals are all small enough to pass through most filters. That’s where the Grayl Ultralight comes in. Instead of small-diameter holes, this filter uses an electrical charge to remove impurities.
The Ultralight works much like a French press coffee maker. You fill the outer sheath of the filter with dirty water and press the filter down into the sheath. Then, you drink the clean water that’s now above the filter. It’s an elegant design and a sturdy one, as Grayl claims that the filter system can be frozen three times before it becomes ineffective – great if you accidentally leave it out on a cold night.
The problem with this type of technology is that it clogs rapidly (the Ultralight is only supposed to filter 150 liters before the cartridge needs replacement), and it’s expensive. With a medium-sized hiking group, you could exceed its capacity during a week-long trip.
The Grayl Ultralight could be a good filter for someone who doesn’t intend to use it very often, but needs it to filter out everything (viruses, chemicals, heavy metals) when they do.
Pros:
- Comes with its own water bottle
- Removes viruses, some chemicals, and heavy metals
- Won’t break if frozen
Cons:
- Filter doesn’t last very long
- Hard to press cylinder down
- High price for its functionality
Lifestraw Personal Water Filter
The Lifestraw might be the cheapest, lightest, and most compact water filter on the market. No surprise since developing countries, where water is often of dubious quality, was its original market. The Lifestraw’s hollow fiber membrane is capable of filtering pollutants of at least 0.2 microns, which is perfect for removing sediment, bacteria, and protozoans.
While it’s possible to drink directly from the source (and some of Lifestraw’s most popular ads feature children drinking through the straw from muddy ponds), most users fill their bottle with unfiltered water and then suck it through the Lifestraw as they get thirsty. However, a problem that often goes unnoticed with this filter is that you can’t carry any clean water with you. And as there’s no way to pull dirty water through the filter besides your own sucking action, the Lifestraw cannot be used to provide clean water to a group.
Another big problem with the Lifestraw is that it clogs quickly if you’re drinking from turbid water. Unlike some of the pump filters, you’ll know that the straw is clogging, as it will be increasingly more difficult to suck water through.
If you’re not hiking or camping very often or just need a filter to use in emergencies, the Lifestraw could be a good choice. It’s also ideal for ultralight backpackers who need to cut out every unnecessary ounce.
Pros:
- Compact design
- Very inexpensive
- Proven track record in developing countries
Cons:
- Very hard to use
- Clogs quickly
- Cannot carry clean water with you or filter water for others
Our Favourite Backpacking Water Filter
This is a tough call, as each of the camping water filters reviewed here targets a specific niche market. In order to select the right one, it’s important to think carefully about where and how often you’ll be using your filter.
Overall, though, we’re going to declare the winner to be the best all-around filter: Katadyn’s Vario. While the Guardian is capable of filtering out viruses and the Lifestraw weighs less, the Vario is adequate in all categories. It has excellent longevity, a fast pump action, and the ability to remove all pollutants besides viruses. If you use this filter for water sources where that could be a problem, just add a few drops of household bleach to kill them.
