Having a backup safe drinking supply is probably the most important tool you can have for not only emergency preparedness and survival but even for camping, hiking or any outdoor activity. You will not last very long in the wild without clean water.
So here we put together a list of some of the best survival water filters we have found through our own personal use, reviews taken from friends and our own research.
Best Water Filters For Survival and Emergency Situations
- Survivor Filter Pro – Best Overall Emergency Survival Filter
- GRAYL Geopress Water Purifier – Best Press Purifier
- CrazyCap 2.0 – Best UV Water Purifier
- MSR Guardian Water Purifier Pump – Best Heavy Duty Filter
- Sawyer Squeeze – Best Small & Fast Filter
- Lifestraw Flex with Gravity Bag – Best Portable Water Filter
- Platypus GravityWorks filter – Best Gravity Filter
1. Survivor Filter Pro
Best Overall Emergency Survival Filter
Pros: Huge overall capacity, Sturdy pump based with decent flow, Nice warranty, The best filter rating on the budget market, Lightweight (0.51lbs), Affordable considering the above, Pippet backwash works well
Cons: The metal-reducing carbon filter needs to be replaced every 2000 litres, The floaty bit doesn’t get sit underwater super well in small puddles, Pump could be tedious for some
Description: The Survival Filter Pro is one of the most effective and affordable purifiers on the market today. This system filters everything, really everything, even viruses, metals & chemicals.
It comes with a very high capacity rating, is easy to use, requires little maintenance, and is built well enough that they offer a lifetime warranty! Being pump based allows you to filter as much as you need without being restricted by anything other than the water supply and your patience.
We like finding products that are ready to stand up to the toughest survival conditions. It was therefore no doubt that we fell in love with the Survivor Filter as it ticks all the boxes needed to keep us hydrated when in a tight pinch. It is a pump based 3-tier filter that has one of the best rated purification standards on the market today. Having used it extensively on questionable water sources in Asia, the metal & chemical reducing carbon filter proved to be a life (and taste) saver.
For such a heavy duty filter the Survivor Filter Pro is very affordable. It is also built to a very high standard while remaining lightweight. Two of the main filters have a capacity rated at 100,000 litres. We found the pump doesn’t clog very easily. We personally like pumping filters for their ability to treat large volumes of water when need be, the Survivor Filter Pro was great at this but it’s flow rate isn’t as high as others on this list.
One thing that we noticed is that it is a bit difficult to use in shallow puddles of water as the float prevents from standing upright and submerging all of the inflow end, but it is still manageable with a bit of a balancing act. Also, while the carbon filter works wonders at removing bad taste, metals & chemicals the capacity comes in at a low 2000L. For this reason we’d recommend buying a spare or two when planning long term.
2. GRAYL Geopress Water Purifier
Best Press Purifier
Pros: Innovative design, Great purification standards, Very fast purification
Cons: Low capacity before needing replacement, Bit bulky
Description: The design on this purifier is very clever, delivering amazing water purification standards in a quick and easy to use manner. Within 20 seconds (manufacturers say 8 but we prefer to go slow) you can have completely purified water from any source as this thing pushes through turbid water as if it were crystal clear.
Although the concept is excellent it appears GRAYL bottles haven’t quite reached their peak performance yet (across all their models) as there are still a few downsides. Firstly the low filter capacity of 250L is really a limiting factor when using this as your primary purifier. It would be ideal for the occasional emergency though. Secondly the design is a bit bulky for it’s 700ML (24oz) capacity. Lastly, at times a suction forms which can make it difficult to remove the inner bottle from the outer bottle after a full press.
Overall, we love this bottle and it is the best press purifier on the market today, giving outstanding water quality removing all pathogens and even metals & chemicals. We would definitely recommend this if you aren’t in need of filtering thousands of liters but need a purification system for occasional use.
3. CrazyCap 2.0
Best UV Water Purifier
Pros: Extremely effective against all unwanted lifeforms, Fast and super easy purification mode, Very durable, drop proof bottle, No swishing or stirring required, Waterproof top, Very good battery life with quick charge, Removable cap can be used to treat other surfaces
Cons: Not very cheap, Battery powered could have problems with extreme heat or cold, Requires transparent water and therefore pre-filtering, Charger is unique and therefore hard to replace, Can only purify and hold a small capacity at a time
Description: For a long time when we thought “UV purifier”, we looked no further than the SteriPEN (now Ultra). That was until this ingenious design came along and took our hearts away. The CrazyCap improves on the SteriPEN by being a super easy to use device that purifies fast and has an incredible lifespan of 236,000 Litres (62,500 gallons).
Like all UV Filters the water itself must be transparent for the UV Light to work its harmful-yet-wonderful magic, so in a survival situation a pre-filter is needed to remove particles and mud. Once this is done, all you need to purify water is to fill her up, press twice on the lid to activate regular mode (which kills 99.6% of contaminates), wait 60 seconds and voila, your water is safe to drink! For those wanting that maximum reassuring cleanliness there’s also the Crazy Mode with 5 taps which lasts 90 seconds and kills 99.99999%!
Not only is the purification super effective it’s also very well built. Drop proof, fully waterproof, finger recognition (for no accidental turn ons) and an excellent battery life offering a week of regular use. One nice extra feature is the cap can be removed allowing it to treat larger quantities of water (taking more time) or even for treating anything that is prone to bacteria like phones and keyboards!
4. MSR Guardian Water Purifier Pump
Best Heavy Duty Filter Solution for the Polluted Water
Pros: Best pumping mechanism we’ve seen, Has an inbuilt backflushing mechanism meaning you don’t need to clean or maintain, 10,000+ litre (2500 Gal) capacity, Complete pathogen filtration, Handles murky water like nothing
Cons: Very expensive, Replacement filters are also expensive, Doesn’t filter heavy metals or chemicals, Is known to have an issue with the seal which can be avoided (and fixed)
Description: We’ve always been fans of MSR, they provide all-round top-quality outdoor gear, so it should come at no surprise that they should feature on this list. This military grade hand pump filter gets through all living contaminants (including viruses) very fast and with ease. It’s worth noting though that it does nothing to heavy metals and chemicals, so if you’re drinking water that’s passed through developed civilisation you might want to consider another solution.
What we love the most about the MSR is how consistent the flow is regardless of the turbidity of the water. It has a very clever self cleaning mechanism which uses roughly 10% of the flow from every pump to backflush the system. This means you can keep pumping away and it’ll consistently deliver at an average of 1 Litre in 35 seconds (depending on murkiness).
In terms of water purification, drop-proof build quality and ease of use the Guardian is close to unparalleled. It does however come at quite the premium, is quite large, and weighing in at 1.04 pounds (~1/2kg) is somewhat heavy. For those looking for a reliable water purifier capable of dishing out litres of water with minimal effort, even amongst the harshest of conditions, this one’s for you.
Best Walter Filters For Variable Situations
These solutions are so adaptable they should be considered more of a tool than a purifier. Unfortunately, to reach this level of adaptability and multi-use, they need to be small in size which means forfeiting the ability to filter viruses.
These are not exactly what you should call purifiers in how we would normally define it but they are water filters they just have a different capacity.
5. Sawyer Squeeze
Best Small & Fast Filter
Pros: Very versatile, many applications, Great flow (much better than the Sawyer Mini or Micro Squeeze), Fast filtration, 45 seconds for 1 litre, Great longevity and build quality, Very affordable
Cons: Sadly doesn’t do viruses or heavy metals, The provided pouches break easily (although are better on this model than others), Needs cleaning very regularly
Description: The Sawyer Squeeze is an impressive, well designed portable water filter that is capable of providing up to 440,000 litres (100,000 gallons) of clean & safe drinking water. This is insane for a filter this small. While other models exist that are more lightweight we prefer the full-sized squeeze for it’s improved flow rate over the others.
What we love about the squeeze is how well the design fits to your water filtration needs. Originally designed for water to be squeezed through the filter for it to work, it turns out it can do much more thanks to its great flow rate. It has the connectivity to provide an easy in-line attachment when used with a water bladder, it screws onto plastic water bottles, and if you’re the type who likes getting really close to your murky water (some do) it works as a straw. For an experiment we even tried to turn it into a gravity filter which worked surprisingly well filtering about 1 litres in an acceptable 2 minutes compared to 45 seconds when squeezing!
Some downsides include needing to backflush it regularly with a cheap syringe, the squeeze pouches that come with the kit are quite poor and will break quickly, and of course the fact that this will do nothing to filter viruses or metals. Overall, the build quality, design and ease of use make this one of our personal favourites when out in the wilderness.
6. Lifestraw Flex with Gravity Bag
Best Portable Water Filter
Pros: Doesn’t clog easily, Removes heavy metals & chemicals, Versatile, Very Affordable, Reliable build quality
Cons: Flow rate is not as good as the basic Lifestraw or Sawyer Squeeze, Difficult to inline, Very low carbon capsule filter capacity 100L (25 Gal), Air bubbles can block the filtration
Description: When it comes to water filters, Lifestraw has always been a keen favourite of ours, however we found that filtering through suction has a lot of limitations, especially when you need clean water for more than just drinking. The Lifestraw Flex solves this issue by being a removable and versatile filter that can be used as an inline, bottle, gravity bag, or direct suction filter. Overall filtration has improved too by adding in a carbon filter which provides a second layer of protection against chemicals & heavy metals. Not only is this safer with questionable water sources but it makes water taste cleaner.
Compared to the bottle on the LifeStraw Flex Soft Bottle the gravity bag in this model is very durably made and comes with a sturdy hanging handle. For us when filtering relatively clear water using the gravity bag, it treated 2 Litres in a respectable 10 minutes. However, this slowed down a lot with turbid water.
Sadly the Lifestraw Flex’s microfiltration membrane is only good for 2000 litres (500 Gal), which isn’t the kind of capacity one would desire for long use. Even worse is the heavy metal reducing carbon filter which only lasts 100 litres (25 gal), considering this system can works well as a group filter, this is not much at all. Another bummer is it is difficult to suck the water through the filter, even with pre-filtered clear water. This makes it difficult to use as an in-line water filter.
Bottom line is, if you can deal with reduced flow-rate this is an excellent filtration system that offers near purification levels of water sanity for an attractive price. Just make sure to bring some extra carbon filters with you!
7. Platypus GravityWorks filter
Best Gravity Filter
Pros: Easiest filter on the list, Filters 4 litres at a time, Great for groups, Lightweight (11oz, 300g), Easy cleaning
Cons: Clogs often with murky water, Can’t be fully filled in shallow puddles, Doesn’t treat viruses, chemicals or heavy metals, 1500 litre filter capacity isn’t huge
Description: The GravityWorks by Platypus is a very simple two bag, high capacity gravity water filter (not purifier) that was built to last. It comes with very few moving parts that are all attached and made to a high standard, meaning no water leaking or tears that occur on cheaper water bladders.
For those who are a bit tired of the pumping, squeezing and sucking required with most other filters, a gravity filter is a great option. With the GravityWorks it’s particularly easy. Fill up the dirty bag, hang it somewhere for maximum 5 mins and viola, clear water appears in the second bag. This can even be done while on the go. The filtration on this system is considerably faster than the Lifestraw Flex and the bags have a larger capacity making it a great option for those in groups.
Like all filters, it requires a backflush, but no dismantling, scrubbing & syringe are required… one only needs to place the clean bag above the dirty bag and once the water has fully passed through it’s been flushed!
Overall we feel this is an excellent option as it packs down quite small, doesn’t weigh much and provides great amounts of water in minimal time very easily. It is not the cheapest on our list but the double-bag design & build quality make it a worthwhile investment.
Cheap Shorterm Use Water Purifying Alternative
Aquamira Chlorine Dioxide Water Treatment
Best for Low Cost Option For Emergencies
Pros: Affordable (as a backup), Extremely lightweight & compact, Fast acting on anything but Crypto, Extremely effective rated 99.9+% for viruses, bacteria & protozoa, Not much taste at all , Can treat as much water as you like
Cons: Requires pre-filtering manually to remove residue and debris, Doesn’t remove microplastics & chemicals, Can be expensive per litre (as a primary purification solution)
Description: Any outdoor survivalist will tell you it’s a very good idea to have a backup way to purify water in case something happens to your main one. Compared to bad tasting and less effective Iodine based tablets, Chlorine Dioxide makes for a much more enjoyable water treatment experience leaving barely any taste.
The Aquamira Chlorine Dioxide solutions come in tablet and liquid form. Having used these in numerous emergency situations we have grown quite fond of their ease of use and fast acting purification speed. Because the initial mixing of the two components takes 5 minutes, with a minimum of 15 minutes activation time, it’s a good idea to start when setting up camp. If you happen to be in an area with cryptosporidium you’ll need to plan further ahead before using this as it can take up to 4 hours to pierce the hard shell of the cysts and kill them.
If you can tolerate this purification time then this inexpensive water treatment system will be a great addition to your pack. It’s so light that you won’t notice it’s there until it’s time to use it. Do note that you’ll need to pre-filter murky water you wish to treat with something like a handkerchief before using these drops, unless you’re the kind that likes gritty, sediment flavoured water.
How To Find the Best Water Filter Out There for Emergency Situations
Water is life. It’s the first thing scientists look for when scouting for life hosting planets and it’s the first thing you should scout for when out in the wild. Although roughly 33% of our water intake comes from breathing in the humidity in the air, this isn’t enough to survive.
The general statistic given is 3 days without a sip and you’re finished. What they don’t tell you however is that within 30 hours of not drinking, the tiredness, dizziness and diminished alertness will make your task of finding drinkable water considerably more difficult.
This is why, as many know, it’s the most important factor of outdoor survival, regardless of your reason for being outdoors. On day or overnight outings, one can fairly easily carry a supply of clean water. When hours turn into days, and you’re looking at roughly 3 litres (3 quarts) of water per day weighing 3kgs (6.6 pounds), this just isn’t manageable. In the true spirit of an effective survivalist, being self-sufficient is the only way to go.
This isn’t as easy as just finding any water source and filling your gourde straight away. No sir (or madam), only 1% of the freshwater on the planet is easily accessible, and not much of it is safe to drink from. Even when you find nice fresh streams coming straight off the hills, there could be a dead creature or some faeces contaminating the stream 100 metres upstream. Excluding man-made chemicals and salts, it is viruses, bacteria & protozoa that turn precious water into a potentially life-threatening liquid.
To overcome this you are going to need to be able to treat water and make it safe to drink and use. Luckily this technology never stops improving, meaning portable water purification systems are now very compact, affordable and attractive for bushcrafters, trekkers & survivalists. The best of these can keep you hydrated by treating any source, no matter the conditions, no matter where you are in the world.
What Makes The Best Water Filter the ‘Best’
Know your enemy
To know what makes a good water purifier, you first have to know a little bit about the enemies that you may face in contaminated water.
Viruses are very simple disease-causing microorganisms that are tiny, the smallest of the lot. They have only the bare minimum material needed to survive and replicate, and can only do so inside another organism.
In North America and Europe waterborne viruses aren’t super prevalent and the ones that are there are not lethal. If traveling to, or living in, destinations with lesser standards of water sanitation, they can be a lot more dangerous.
Only a certified purifier can handle viruses, most microfilters won’t be enough as the filter size is often not small enough to catch them.
Bacteria (also called “germs”) are microscopic single-celled organisms that have a tendency to survive in the harshest of environments and are present everywhere. Some bacteria are good and some are bad, yet the ones found in water in a survival situation tend to be the unwanted kind. The most common ones found and known are E. Coli & Salmonella which aren’t lethal but much, much worse is out there.
Luckily, every water treatment solution (applied correctly) will remove or kill bacteria.
Protozoa are also single-celled organisms, very similar to bacteria but containing more inside the cell making them larger. Water-borne parasites, the most common in the northern hemisphere being Giardia, fall into this category. Although these are some of the nastiest things hiding inside untreated water, they are also the easiest to filter out due to their large size.
Any water purification system will handle these.
4. Chemicals, Metals and Microplastics
We humans have had a pretty awful impact on the world’s water supply, and other natural resources too. Our industrial materials have leaked and spilled everywhere from oceans, to rivers to water aquifers deep beneath the ground.
What this means is that depending on where you are, you might need something heavy duty that can prevent these unwanted substances from entering your drinking water. We’re talking toxic heavy metals such as lead and mercury, chemicals such as pesticides & herbicides & plastics too small to see with the naked eye. Yuck.
What to look for in a Water Purification System
1. Treatment Tating
As we mentioned there’s a difference between a purifier and a filter. If you are expecting viruses to be in your area or you want to be prepared for anything, a purifier is the way to go. If the purifier is filter based, such as the Survival Filter Pro or the MSR Guardian, you would expect a filter size of 0.02 micrometers or less to be able to catch viruses.
A good thing to look out for when choosing your purifier is testing done by an independent researcher. This will normally give a rating which you can trust on.
2. Purification Speed
Depending on the method, purification time can vary greatly. Thanks to advances in nano-technology, most water purifiers now use some form of filtration combined with other stages to treat different unwanted contaminants.
This makes them pretty fast (almost instant) compared to the older technologies of chemical or UV treating (1-60+ minutes). This does not mean the latter by any means that the later are not relevant in today’s water purification scene but that they require a bit more planning.
3. Purification Method
We’ve come a long way from boiling our water when in an emergency and there are now three main options for purifying water:
- Filter – A force is needed to push the water through the filter either through sucking, pushing, using gravity or a pump. These can generally filter water quickly and provide good water quality.
- UV Light purification – The water to be treated is exposed to UV light which fries the DNA of the pathogens preventing them from reproducing meaning no infection! Overall great against pathogens but doesn’t filter any dirt or more dangerous materials. What’s more is if the water isn’t clear it won’t work. Requires to be charged meaning another battery to be dependent on…
- Chemical treatment – Chemical treatment involves mixing chemicals in the water that will kill pathogens. Similarly to the above, this doesn’t filter the water meaning you’ll have to do that yourself but it does work in murky water. Normally quite cheap per unit but are more expensive per litre than filters. Very lightweight and therefore make for excellent backups. The treatment time is comparatively very long (15-240 mins).
How many litres can you treat before you have to replace the system and how much can you treat in one go?
Some purifiers are amazingly effective but their treatment capacity can be quite low before needing to replace. Others like the CrazyCap can last for thousands of litres but can only treat a little bit at a time.
These factors are important when it comes to planning your emergency water purifier. You need an idea if you’re planning for yourself or for many, as well as how long you plan to depend on wild water.
5. Cleaning and Maintenance
This only applies to the filter type purifiers. Most filters will get clogged after regular use but are designed with a way to clean them and flush out the accumulated particles. This is generally called backwashing. However, not all backwashing methods are created equal, some can be done via pipet making them fiddly or slow, and some, like the original Lifestraw, can be cleared just by blowing air back into the filter. Some even clean themselves!
6. Cost Effectiveness
It’s good to look at price per litre to determine your main water purifier so that’s not only making the water lighter but also your wallet. Chemical based solutions are cheap per unit but don’t treat very much water in the long run.
Make sure you look at how much replacement parts cost for filters as once they have used up their capacity they are no longer safe, or sometimes efficient, to use.
In our opinion, a water purifier, whether kept for an emergency or regular use, will be among the most important gear in your pack. Even if you live in an area where the water comes straight from the mountaintop and is purer than pure, you never know where your next emergency situation will be.
Purifiers often fall into the same category as a medkit, better to have it and not need it than to need it and not have it. Be sure to find out what contaminants you’re likely to find in your outdoor environment before deciding on a system.