6 Best Backpacking Water Filters of 2018
Clean drinking water is an incredibly important consideration for any trip into the backcountry. If you’ve ever had the pleasure of experiencing a stomach parasite (we have, it’s awful), then you already know how critical clean drinking water is. If you haven’t, good! Let’s keep it that way.
For any extended trip into the wilderness you’ll want a treatment method for cleaning your drinking water. But when you start shopping for a good filter or purifier, you’ll quickly find that there are A LOT of different products out there.
We put together this guide to explain key treatment method differences and to share our personal favorite products. We’ve spent hundreds of hours researching and testing these tools, so we hope you find this information helpful.
If you like this guide, you’ll probably like our other gear guides as well. Below are links a few of the most popular sections of the CleverHiker Backpacking Gear Guide, which we update regularly.
WEIGHT: 2 oz
PROS: Ultralight, easy, affordable, kills viruses
CONS: Wait time necessary
We almost always backpack with chlorine dioxide water treatment. At very least, we carry it in pill form as a backup if our main filtration system malfunctions, clogs, breaks, or loses battery. We also often use it in drop form as our main treatment method because it’s affordable, easy to use, and nearly hassle free. We hardly notice any taste or smell with chlorine dioxide, but waiting time is required for it to work (see "wait time" section below). The drops are more affordable per liter, but you have to pre-mix them and wait 5 minutes before adding them to your water. The pills are more expensive, but they’re easier to use: just plop one into a liter of water and wait for it to work. When using chlorine dioxide as our main treatment method, we usually bring both pills and drops, then use whatever’s most convenient at the time.
WAIT TIME: In order for chlorine dioxide to be effective against cryptosporidium, a 4 hour wait time is required. Giardia, bacteria, and viruses are all killed in about 30 minutes, but crypto takes longer to kill. When we judge a backcountry water source to be clean (read "judge the source" section above), we normally wait 30 minutes after treating with chlorine dioxide before drinking. If we don’t trust the water source, we wait the full 4 hours. Obviously, this is a personal choice that’s up to you.
WEIGHT: 4.8 oz
PROS: Lightweight, very convenient, fast, neutralizes viruses
CONS: Expensive, battery powered, won’t work in murky water
We love the convenience and speed of the SteriPen Ultra UV light purifier. When paired with a small-mouth, 1L plastic bottle (ex: Smartwater), the Ultra is just about the fastest and easiest water treatment method we’ve ever used. Simply place the Ultra in your water bottle, flip it upside down, gently agitate for 90 seconds, and you’ve got a clean liter of water. We don’t love that the Ultra is battery powered, but we’ve grown to trust it over time. We can purify about 5 days of water for 2 people (50+ liters) with the Ultra’s rechargeable internal battery. The biggest downside with UV treatments is that they don’t work in murky water, so we always carry backup pills and a pre-filter (ex: pantyhose) just in case.
LEARN MORE: CleverHiker SteriPen Ultra Review
WEIGHT: 11.5 oz
PROS: Very convenient, good for groups
CONS: Heavy, expensive, doesn’t filter viruses
The convenience of the Platypus GravityWorks is tough to beat, especially for large groups. To use the GravityWorks, simply fill up the “dirty” water bag, hang it above the “clean” bag, and let gravity do its thing. The main benefit? No tedious pumping or squeezing required. This is especially beneficial for large groups, when filtering a lot of water can quickly become obnoxious. There is a downside to the convenience of the GravityWorks, and it comes in the form of weight. We prefer to travel as light as possible on our backcountry trips, so we only take the GravityWorks when we can share its weight with a group. Platypus also makes the GravityWorks in a 2 liter system and 2 liter bottle kit, but we prefer the 4 liter model.
Like most filters, the flow rate of the GravityWorks will diminish over time depending on how dirty the water you filter is. Periodic backflushing will help with flow rates, but eventually the filtration unit will need to be replaced. Like most filters designed for the US market, the GravityWorks won’t filter out viruses (read “Viruses” section above), but that shouldn’t be a dealbreaker unless you plan to use it internationally.
WEIGHT: 5.2 oz
PROS: Affordable, lightweight, good for shallow sources, pre-filter attached
CONS: Hand pumping required, doesn’t filter viruses
The MSR Trail Shot is a lightweight and affordable hand pump filter for the trail. One of its key benefits is the ability to pump water from shallow streams and puddles, which can sometimes be very useful in the backcountry. You can drink straight from the Trail Shot or fill bottles directly, but the tip of the Trail Shot can also be paired with a water tube, which makes filling bottles and bladders easy. Like most pump/squeeze filters, hand squeezing 4-6 liters per day with the Trail Shot can get annoying, but it's not as bad as we would have thought. Also, the Trail Shot has a short intake tube, so you’ll have to hunker down close to sources for pumping, but again it's not too bad.
Like most filters, the flow rate of the Trail Shot will diminish over time depending on how dirty the water you filter is, but it does have a built in pre-filter which helps. Periodic backflushing will help with flow rates, but eventually the filtration unit will need to be replaced. Like most filters designed for the US market, the Trail Shot won’t filter out viruses (read “Viruses” section above), but that shouldn’t be a dealbreaker unless you plan to use it internationally.
WEIGHT: 3 oz (filter only)
PROS: Lightweight, affordable
CONS: Squeezing gets annoying, squeeze bags eventually break, doesn’t filter viruses
The Sawyer Squeeze is a lightweight and affordable backcountry water filter. It can be used in a variety of different ways, but we find it works best with 64 oz squeeze bags. To filter water, simply fill up the bag, screw on the Squeeze, and put pressure on the bag to force water through the filter. Our biggest qualm with the Squeeze is that the squeeze bags tend to wear down and break over time, so we recommend traveling with a replacement bag. Also, we find the squeezing process can become rather tedious over time, especially for large groups. The Squeeze also comes in a cheaper and lighter Mini version, but the cost/weight savings aren’t quite worth the reduced flow rate over time in our opinion.
Like most filters, the flow rate of the Squeeze will diminish over time depending on how dirty the water you filter is. Periodic backflushing will help with flow rates, but eventually the filtration unit will need to be replaced. Like most filters designed for the US market, the Squeeze won’t filter out viruses (read “Viruses” section above), but that shouldn’t be a dealbreaker unless you plan to use it internationally.
WEIGHT: 17.3 oz
PROS: Fast, military-grade quality, minimal maintenance, filters viruses, pre-filter attached
CONS: Very heavy, very expensive
The MSR Guardian is a top-of-the-line pump purifier built for the harshest conditions. Unlike most pump filters, the Guardian is a purifier, meaning it filters out viruses in addition to bacteria and protozoa. This makes it particularly useful for truly terrible water sources, especially in international destinations. The Guardian is also “self-cleaning,” meaning is automatically backflushes with about 10% of every stroke. This keeps its flow rate high, pumping fatigue down, and maintenance to a minimum. We've found the flow rate of the Guardian to be very impressive, and consider it the fastest filter we've ever used. For ease of use, the guardian is best when paired with a wide-mouth Nalgene bottle .
Our two main gripes with the Guardian are cost and weight. Though it’s built to withstand many years of rugged use, the upfront cost of the Guardian is pretty staggering. In addition, the Guardian is heavier than almost any water filter we’ve used, which makes it hard to justify on our backcountry trips. That said, if you’re looking for best-in-class protection from a tool that’ll pull clean drinking water from a murky mud puddle in India, the Guardian is your guy.
The following filters didn’t make our final list, but they still have a lot of good things going for them. In this section we'll quickly highlight each filter's main strengths and explain why it didn’t make the cut. And you never know, maybe one of these filters will be the right fit for you.
WEIGHT: 2.3 oz
PROS: Affordable, ultralight
CONS: Soft bottle durability, unideal for backpacking, doesn’t filter viruses
The Katadyn BeFree is an affordable, lightweight filter that works well on quick backcountry jaunts. The reason it didn’t make our final list is because we don’t think it’s ideal for the rigors of multi-day backpacking trips. The soft bottle of the BeFree isn’t built to withstand squeeze filtering 4-6 liters per day and hauling water from one source to the next. Also, the filtration unit on the BeFree is relatively small, which impacts its flow rate over time faster than we’d prefer. The BeFree is available in a 3 liter gravity bag model, which is a closer fit, but still has some durability and logistical issues (ex: no hang strap, hose, shut off clamp, or bottle adapters). We like the BeFree for trail running and quick backcountry trips around water sources, but we don’t normally use it as our primary purification method for multi-day backpacking.
WEIGHT: 11 oz
PROS: Dependable, pre-filter attached
CONS: Heavy, pumping required, doesn’t filter viruses
The Katadyn Hiker Pro Clear and previous models have been a staple in the backpacking community for many years with good results. Pump filters like this can pull water from tough to reach sources, which can often be helpful in the backcountry. Our main issue with the Hiker Pro is that it weighs about as much as a gravity filter, but still requires pumping. Comparing cost, weight, and ease of use, we prefer more convenient treatment methods (ex: GravityWorks, SteriPen Ultra) and lightweight, affordable systems (ex: Chlorine Dioxide, MSR Trail Shot, Sawyer Squeeze) over the Hiker Pro. That said, the Hiker Pro will certainly get the job done well and could be a good fit for your backpacking trips.
WEIGHT: 2 oz
PROS: Affordable, ultralight
CONS: Need to lay down to use it, unideal for backpacking, doesn’t filter viruses
The LifeStraw is a very affordable, lightweight filter that’s good for quick backcountry trips around water sources and for use in emergency situations. Our main gripe with the LifeStraw is that you basically have to lay on the ground to use it, which is rarely practical. There is a LifeStraw bottle system, but that doesn’t solve the issue of treating multiple liters for the trail. We still think the LifeStraw is useful for trail running and quick trips, but we don’t use it as a primary treatment method for backpacking.
WEIGHT: 10.9 oz
PROS: Good for international travel, filters viruses
CONS: Heavy, small volume, unideal for backpacking, 300 use filter limit
The Grayl Water Purifier Bottle is a good choice for city travel and quick backcountry trips. The Grayl is a purifier, so it protects against viruses, which makes it great for filtering hotel tap water on our international trips. We like that it helps us cut down on plastic waste and find it far more convenient and cost effective than buying a bunch of water bottles. Our main issue with the Grayl is that it's too heavy and cumbersome for multi-day wilderness backpacking trips, where we need to filter and haul 4-6 liters per day. Also, the filtration unit on the Grays is only rated for 300 uses (40 gal/150 liters) before you'll need a replacement cartridge. Limitations aside, the Grayl is still a great tool for reducing plastic bottle waste on international trips and quick backcountry jaunts.
TREATMENT TYPE PROS AND CONS
Chlorine Dioxide Chemical Treatment
- Works by killing the bad stuff with chemical drops or pills.
- Kills bacteria, protozoa, and viruses.
- Very lightweight and easy to use.
- Relatively affordable (drops normally cost less than pills).
- Relatively foolproof (no clogging, breaking, or maintenance).
- 4 hour wait time required (more info below).
- Unlike other chemical treatments, no funky taste or color.
CHLORINE DIOXIDE WAIT TIME: In order for chlorine dioxide to be effective against cryptosporidium, a 4 hour wait time is required. Giardia, bacteria, and viruses are all killed in about 30 minutes, but crypto takes longer to kill. When we judge a backcountry water source to be clean (read “judge the source” section above), we normally wait 30 minutes after treating with chlorine dioxide. If we don’t trust the water source, we wait the full 4 hours. Obviously, this is a personal choice that’s up to you.
- Work by filtering out the bad stuff and letting clean water pass through.
- Allows you to drink clean, cold water straight away.
- Many filters require work (pumping, squeezing, etc) which can be annoying.
- Gravity filters don’t require much effort and can be good for groups.
- "Filters" are not effective against viruses, but "purifiers" are. (read “viruses” section above).
- Prices vary - pump and gravity filters tend to be more expensive than squeeze filters.
- Weights vary - pump and gravity filters tend to be heavier than squeeze filters.
- Some maintenance normally required (backflushing, cleaning, etc.) to keep up flow rates.
- The flow rate of nearly every water filter will decrease with use. The dirtier the water source, the faster your filter's flow rate will decrease. Eventually the filtration unit will need to be replaced.
- On chilly trips, be careful not to let your filter freeze. Freezing will break the filtration unit.
UV Light Purifiers
- Work by sterilizing the bad stuff with ultraviolet light.
- Sterilizes bacteria, protozoa, and viruses.
- Allows you to drink clean, cold water straight away.
- Requires minimal effort and works quickly.
- UV purifiers tend to be more expensive.
- Requires batteries and could malfunction in the field.
- Clear water required for UV treatment, not a good choice for murky sources.
- Boil water for 1 min (or 3 min over 6,500 feet) to kill bacteria, protozoa, and viruses.
- Requires extra stove fuel and cooling time.
- Not a primary treatment method, but useful when you’re already cooking.
CRITICAL WATER TREATMENT CONSIDERATIONS
LEAVE NO TRACE - It’s gross to think about, but most backcountry water contamination is a result of feces, either from humans or animals. That’s why you can’t talk about clean water without talking about LNT. When you need to crap in the woods, ALWAYS dig a cathole 6-8 inches deep and do your business at least 200 feet from any water source. Use toilet paper sparingly and either bury it thoroughly or pack it out in a ziploc bag. We use a cheap, lightweight snow stake for digging and it works great. C’mon people, you love nature, that’s why you’re out there. So please put in a little effort to keep things clean for generations to come.
PRICE - Water treatment methods vary a great deal in price depending on the style and model you choose. Chemical treatments tend to be the lowest cost option, UV water purifiers tend to be on the more expensive side, and filters run from inexpensive to very expensive depending on the model. We recommend a variety of each method below and heavily factor cost into our choices.
WEIGHT - Weight is a very important factor for any item you plan to carry into the backcountry. At CleverHiker, we’re all about keeping pack weight to a minimum. That allows us to cover more miles using less energy, and ultimately makes backpacking way more fun. You can save close to a pound by choosing a lightweight water treatment option over a heavy alternative, and that will always feel better on the trail. We list weights for all the products we recommend and heavily factor weight into our recommendations.
EASE OF USE - Treating water will be a task you complete multiple times everyday in the backcountry. If you’re purification method is obnoxious, you’re bound to get annoyed with it quickly. In our recommendations below, we always prioritize treatment options that are easy to use and minimize hassle.
BACKUP METHOD - Just like any important backcountry tool, you’ll want to have a backup plan if your water treatment method fails. Water filters can clog, squeeze bags can break, and UV purifier batteries can die. So regardless of your treatment method, we always recommend bringing backup chemical treatment pills. We’ve had to rely on backup pills several times and have always been happy to have them.
JUDGE THE SOURCE - Choosing clean water sources is one of the best ways to avoid contamination in the backcountry. When choosing a water source, look for clear, cold, flowing water. Medium size streams are usually ideal. Lakes can be a good choice as well, but sediment and bacteria do tend to build up around shorelines, so flowing water is preferable. Feces tends to be the biggest culprit in water contamination, so always avoid areas with lots of human or animal activity (pastures or meadows for example). Rain can make matters worse by washing contaminants and sediment into water sources. Snow should always be boiled for about one minute or melted and treated, because it can contain contaminants as well.
PRE-FILTERING - Small bits of organic matter (leaves, algae, etc.) usually pose no threat, but when they’re present, use a pre-filter (bandana, pantyhose, etc.) to strain out sediment before treating your water. When water sources are clear, we don't bother with pre-filtering, but we always bring a small section of pantyhose just in case. Pre-filtering will make any water treatment process more effective and will extend the life of your water filter.
WASH YOUR HANDS - Many people blame water sources when they get sick in the backcountry, but improper hygiene is often the real culprit. A small bottle of hand sanitizer should be considered essential for any backcountry trip. Use it after bathroom breaks and before eating. In the past we would also bring biodegradable soap, but we don't think it's necessary anymore.
VIRUSES - The only difference between a water “filter” and a water “purifier” is that purifiers remove or kill viruses and filters do not. Viruses are rarely a problem in North America, so most US backpackers don’t worry about treating them. However, if you’re planning to treat water abroad, especially in developing countries where people or animals could have contaminated the water, you'll want a treatment method that protects against viruses. Chemical treatments, UV Purifiers, and high-tech pump purifiers (ex: MSR Guardian) protect against viruses.
BOTTLES & BLADDERS - We use small-mouth plastic bottles (ex: Smartwater) on the majority of our backpacking trips. They’re lightweight, affordable, durable, and they last a very long time. When we need to carry lots of water over long dry stretches, we use trusty Platy Bottles to store water in our packs. Some backpackers like to use hydration bladders (ex: Platypus Big Zip), but we generally find them to be too much hassle and we’ve had a few leak in our packs.
BEST - It’s important to remember that what’s “best” for us, might not necessarily be best for you. Water filters are a personal choice, so we work very hard to detail the strengths and weaknesses of each filtration method with the goal of putting decision making power in your hands. In the end, there’s rarely one clear "best" choice, but hopefully we can help you find equipment that will work best for you.
BACKPACKING WATER PURIFICATION VIDEO
As part of our Lightweight Backpacking Gear Basics video series, we put together the video below on ultralight backpacking water filtration. Some of our water treatment choices have changed a bit in the years since the making of this video, but there's still a lot of useful info in there.
If you enjoyed this review, you'll probably like the CleverHiker Backpacking Gear Guide as well. Here are a few links to some popular articles:
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We hope this guide was helpful for finding the backpacking gear you were looking for. If you want to provide feedback or recommend an item we missed, please use our contact form to get in touch.
Thanks for reading and happy trails!
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