One of the biggest problems facing hikers is staying properly hydrated. But no matter how parched you are, the worst thing you could possibly do is just taking a sip form a creek. The truth is, no matter how gorgeous the setting or how sweet and pure the water tastes, there is no way to tell whether or not it is riddled with little bugs that can make you really, really sick. A good portable water filter makes all the difference.

In the 1980s we learned of Giardia lamblia, a microscopic parasite encased in a hard shell (called a protozoan cyst) that makes its home in the intestines of animals and humans. More recently, we have learned of another cyst, Cryptosporidium parvum. Both cause extreme distress in the lower gastrointestinal tract and are highly contagious. They can be difficult to diagnose and treat. The cysts are extremely hardy and can survive out of water for weeks. Furthermore, a person can become ill by ingesting just one of these cysts. You’re at risk pretty much anytime you dip your drinking bottle into open water.

water filtering and purification in camp

Lucky for us, there are a number of water filtration and purification options out there to help make water safe for consumption. Filters provide physical filtration at a micron level, enabling the removal of both giardia and cryptosporidium, as well as removing particulate. The EPA has no standard for testing or approving filters, they are only certified by third-party bodies, though proper use of a filter does provide reasonable protection. Chemicals kill the cysts, but do not remove particles from the water.

Hollow Fiber and Carbon Filters

Hollow fiber filters are very reliable in many real-world water conditions, because they physically remove the contaminants. These filters should not freeze, so if you’re camping and temperatures drop below 32 degrees, consider tucking the filter in your sleeping bag. The negatives of using a filter are the weight and bulk, as well as the time required to stop and filter water, though due to high flow rate, hollow fiber filters can process water fairly quickly.

Filters give the best-tasting water. Pump filters get rid of cryptosporidium, giardia, and bacteria like E. coli, and they use a carbon element to filter out most chemicals and bad tastes, but not viruses. Opt for one only if you’re convinced that viruses will not be a problem in your travels, or if you’re prepared to chemically zap them after you’ve filtered your water. Or boil water on you backpacking propane stove. 

MSR TrailShot Portable Water Filter

This pocked-sized water filter is very compact and light, weighing just 5 ounces. It fits conveniently in an outside pack pocket, though the hose is quite short, so you will have to bend over while pumping water. It is faster than many other filters, even when pumping a lot of water.

Here are few pro tips by Washington Trail Association to get the most from this tiny filter: It is easy to take off the small mesh filter on the intake hose after every 5 liters or so and just give it a quick swirl through water to help clean it. To clean the main compartment, fill it up about half way and put on the cap. Then pull off the bottom hose, give it a good shake with your finger over the outlet, and then let the water drain away. Finally, this pump works much faster if you prime it first. Give about 10 slow pumps, until the reservoir is nearly full, and then fill up your water container.

Sawyer Point One Squeeze

This filtration system is a complete, self-sufficient hydration solution for backpackers. It is lightweight and able to roll up, so it takes up virtually no space in your pack. This system can filter up to 100 000 gallons of water, which means that in theory you could fill a 50ft swimming pool with clean, germ-free drinking water.

The Point One Squeeze Filter system includes two 32 oz squeeze pouches, filter, cleaning plunger, inline hydration pack adapter, gravity tube, and mesh bag with hanging loop. Sawyer Squeeze filter is very versatile, you can use it with included bag, with almost any aftermarket bag, or just screw it directly on to a bottle and drink the water right from the filter. You can also use it in gravity fed systems, as well as inline filter on a water bladder.

Gravity Bags

Gravity bags are an incredibly simple addition to the water cleaning arsenal. There are smaller, more compact filtering devices available, but probably none as easy to use as the Gravity Filter. Simply scoop up water in the extra-large bag, hang it up and kick back while it does all the work for you.

The system consists of a bag, or a pair of bags, one for dirty water and one clean, with hoses running to and from the filter or purifier. It takes some time to filter a gallon of water this way, so it’s not a trailside fix, but in camp, the convenience can’t be beat. Not every filter will run on gravity, but there are ready-made systems that can efficiently and quickly filter water while you set up camp. The MSR Autoflow system works this way, as well as Platypus gravity system with a filter with flow rate of 4 liters in 2.5 minutes.

MSR AutoFlow XL

MSR Autoflow XL is a fast, high-volume water filtration system, perfect for camping. Without any action on your part, the system filters water at an impressive rate of 1.75l per minute, using the filter cartridge based on hollow fiber technology. Just fill the durable RF welded 10 liter bag, hang it and let the gravity do the work. You’ll have clean, safe to drink water for the entire group in minutes.

msr autoflow gravity filter

Platypus GravityWorks 4.0l System

This system includes the dirty water reservoir, a hose for the dirty water reservoir, Gravity Works filter, clean water hose with an attachment to connect to clean water reservoir. It is very easy to use, and easy to clean as well. The hollow fiber filter cartridge can process up to 1500 liters of water before it needs to be replaced. You are also able to easily backflush this filter to clean t and remove any air bubbles.

platypus gravityworks system

UV Water Purifiers

A UV water purifier treats micro-biologically unsafe water with germicidal ultraviolet light. The UV wavelength scrambles the DNA of living organisms in the water, so they can no longer reproduce and make you sick. This type of water purification deactivates living organisms, but does not remove particles, nor bad taste and odor, so it use is alongside filters to provide perfectly clean drinking water.

SteriPEN Adventurer Opti

This lightweight water purifier uses high energy ultra-violet light to blast viruses, bacteria and cysts from your water. This little device is perfect for backcountry hiking, camping trips or even international travel. It is very simple to use, and it decontaminates 1l of water in your water container in 90 seconds.  It can only be used with clear, unfrozen water, any discoloration and debris can limit the penetration of UV light, so you need to use a pre-filter if the water is cloudy or murky. The life of the lamp is 8000 activation cycles which means over 7 years if you use it 3 times EVERY day! The batteries are included.

SteriPEN Classic 3 with Pre-Filter

SteriPEN Classic is the best-selling UV water purifier of all times. It is very effective, as the UV light breaks the DNA of microorganisms making it unable to reproduce and make you sick. There is no pumping, no waiting for chemicals to work, the water is ready to drink as soon as the lamp switches off.

In the pack with SteriPEN Classic 3, you will also get a pre-filter and the wide bottle attachment, which can be used with most wide-mouth bottles. The filter is used to remove small particles and debris from water

Chemical Treatment

Sure, a pump filter will remove harmful microorganisms from water. You still need a viricide though—think chlorine bleach, chlorine dioxide, or iodine—to finish off the really small, really nasty stuff like Norovirus, a well-known ‘stomach flu’. All these chemicals work, but some are less effective in very cold or murky water. And remember: viricides are poison; read, memorize and follow the instructions. Be aware: Iodine does not kill cryptosporidium, and bleach (sodium hypochlorite) is not considered a safe water-purification method.

If you like to backpack light, carry only as much as you need (and a little extra) to get you to the next good water source. Instead of carrying a bulky water filter, opt for Aquamira water treatment drops or chlorine dioxide purification tablets. Both are effective without the icky taste of iodine.

Aquamira Water Treatment

For serious water treatment in nearly every situation, you can rely on Aquamira Water Treatment, a two-part liquid solution. It’s a simple, lightweight, and inexpensive option. Each kit contains everything you need to treat up to 30 gallons of water. The active ingredient is chlorine dioxide, the stuff used in municipal water purification. Aqua Mira does change the flavor of the water slightly, but it’s not unpleasant. Tablets with the same active ingredient are also available and are great as a backup, but they are more expensive.

Water Bottle with Filter

On the trail you obviously need something that will hold your water. There are two options: a collapsible water reservoir (water bladder) and a hard sides water bottle. The advantage of water bottles is that there are options that come with filter, so you get a full water filtering/storage system in one. Insulated bottles keep the water fresh and cold and even if they do not come with integrated filters, the wide-mouth opening works with many standard water filter attachments.

Katadyn BeFree

With the ultralight Katadyn BeFree, you can head out on any adventure, no matter the size, without worrying about clean drinking water. Whether it be on a remote trek, out mountain biking, or at a small basecamp by the lake. Just fill the flexible, foldable reservoir with water and be immediately refreshed doing what you love. The BeFree bottle is the perfect companion for hikes, travel, or for everyday use.

Katadyn BeFree is incredibly convenient filter and water container that packs down small enough to fit in your pocket. The EZ-Clean Membrane filter is integrated in the cap with snap closure, catching all the particles down to 0.1 micron. All it takes to clean this filter is to stick it in the water source and swish it around, no extra tools or syringes needs. You can filter up to 1000l before you’ll need a replacement membrane.

Water Filtration FAQ

How do hollow fiber filters work?

Hollow water filters use ultrafiltration membrane technology to catch particulate that is down below 0.025 micron. It centers around microscopic pores in the polymer membrane surface to form a physical barrier to any solids and microorganism in the water. As water flows through the microscopic pores and into the membrane fibers, the particulate, bacteria and viruses are blocked, letting only the treated water pass through.

How to store filters and water containers for camping?

The most important thing with any hydration equipment before storing it for the season is to make sure it is completely clean and dry, otherwise you risk bacteria or mold growing in there, which can taste horrible, and give you a bit of a stomach bug to. Remove filter from its housing and dry everything completely before storage. Thoroughly sanitize and dry hydration bags and water bottles completely before storage. Remember to remove batteries from MIOX water purifiers.

How to prevent water filter from freezing in cold weather?

When temperatures drop below freezing, portable water filters are not the solution for your hydration needs. If you get water into the filter, it will freeze, expand and begin breaking all of the seals inside your filter, making it no longer effective. So when it’s cold, leave the filters behind and turn to one of the alternatives such as tablets, electronic purifiers and good old-fashioned boiling.

There are a lot of backcountry water filtration systems that you can use out on the trail, but which one is the best? Well, which portable water filter or water purifier you’ll choose, depends on your need. Are you camping in a tent or camper van? Gravity filter systems are a given. For hiking and backpacking, we would recommend MSR filters, Sawyer Squeeze or Katadyn BeFree. And having a water purification tablets of droplets is always a good idea, as they take up virtually no space at all, but can be a vital backup option for making water germ-free and good to drink.