I’ll just get this out of the way right up front because if you take one thing away from this article this should probably be it: Be wary of the claims made by water filter manufacturers.
First thing to do when researching and deciding on a portable water filter is to consider what your use is going to be? Some manufactures make absurd claims about filter life, like stating that theirs will last for 100k gallons of water. I steer clear of companies who make laughable assertions about products my life depends on and recommend that you do likewise. In my opinion, it is reckless and reprehensible to tell consumers that a hollow microfiber mini filter will do 100K gallons of surface water. It would take over a year of non-stop testing. Add in backwashing, it needing to be reversed, and this filter wasn’t even around long enough when they made that claim.
At most, people drink a gallon or so of drinking water per day. I have filtered a lot of water over the years with a lot of filters. In several days of backpacking, I typically filter a few gallons of water for myself and for others. When cleaning the different filter elements and/or back flush, I see how dirty my filters get and how much wear they take. I don’t believe any mini filter will last 100K gallons. They will develop erosion and fractures long before that, especially a hollow microfiber filter. Three or four lifetimes worth of filtered water from a $20 filter sounds great, but the company might as well sell perpetual motion machines.
It is easier to trust companies that test extensively and advertise realistic results published by accredited 3rd parties. I’m a technical guy, with a high tolerance for tech-babble, but also see it for what it is. Some filter companies are getting their filters tested by little labs in far flung corners of the world or by universities with water labs you have probably never heard of. They make up high tech sounding names for “new technologies” or reference features like extremely small pore sizes. None of this means anything if the filter erodes, develops tiny cracks, or gets clogged long before it meets some theoretical end of life.
The only certifications that I can see really mean anything are NSF/ANSI and EPA standards. Anything else may just mean the manufacturer paid some lab or know somebody at a university lab.
Generally I’m wary of any claims of special new technology. The whole filter has to work, not just one cool feature. If it stops working, the only way you’ll know is when you get sick with a waterborne illness.
One technology especially that I would steer clear of is a hollow microfiber filter. Especially if you live anywhere with freezing weather. Even microscopic amounts of water will crack microtubules when it freezes and there is no way to tell that this has happened until you get sick.
Which Filter to Buy vs How to Use It Effectively
Most folks focus too much on which product to buy and not enough on how to use it effectively.
If you have a sound understanding of water treatment and preventing waterborne illness, you are better off than an uneducated person with a great filter. For instance, you’re as likely to be infected with giardia from not washing your hands before eating from drinking untreated surface water. Giardia cysts are in fecal matter and they’re pretty much everywhere.
Filter Use – A few pointers will reduce pathogens before the water ever gets to your filter which will also extend filter life.
- Wash your hands frequently with soap and water. After relieving yourself, before eating, after handling or preparing game, and before you handle your filter. Wash between fingers, the backs of your hands, under fingernails, and then dry your hands.
- Most parasites and pathogens are too small to see. The fact that water appears clean and inviting doesn’t mean it isn’t contaminated.
- The water that goes in impacts portable filter life to a much greater extent than larger filtration systems. Mud, minerals, and biomatter clog filters and wear away at them. If you need your filter to last extra long, remove water with a bucket or basin, strain it through a couple layers of cloth then let it settle.
- When drawing water from a natural source, don’t draw it right at the surface. The surface tension and proximity to oxygen supports greater bio-density, including all sorts of pathogens. Don’t put a filter intake on the bottom or it can suck up mud or silt. For this reason, some quality filters come with adjustable floats on the intake hose.
- If you filter from fast moving water like a river, don’t draw it from the center because the water will churn up the bottom. Draw it from a slow moving, although not stagnant, spot near the bank. Don’t get too close though because there will be more biomatter.
“First vs Third World Countries” and Virus Protection
At least one popular filter manufacturer seems to think that while developing nations are ankle deep in raw sewage, viruses simply cannot survive in water here in the USA. It’s true that children in developing nations are hardest hit by waterborne illnesses, but I’m pretty sure that pathogens do not respect geopolitical boundaries.
The USA is only ever a pandemic, cyberattack, EMP, nuclear conflict, or financial collapse away from being a developing nation again. So keep that in mind when you are sizing up portable filters and weighing whether you want it to kill viruses.
Pore sizes in filters elements are typically too large to filter out all viruses. Filters effective against viruses typically employ some type of chemical treatment to do so. Some models have replaceable filter elements or add-on virus protection. Adding protection against viruses typically means increased cost and decreased flow rate, but this is a small price to pay if you need protection against viruses.
Portable Filters Types
It used to be that portable filter users had three or four different form factors to choose from. They all used different (and proprietary) filter elements. Now filter manufacturers apply modularity to filters (which I am such a huge fan of that I pioneered the modular survival kit and still do). You can now buy a single filter that can be used in several form factors or a specialty filter in a form factor that you prefer:
Filter Straw – While I don’t recommend doing this in crocodile or alligator country, filter straws enable you to kneel at the edge of a water sources and drink from it.It involves sucking water through a straw-like tube.
The tube can be the filter body itself or a tube connected to the input of a multi-use filter.
- Some models are small enough to realistically carry in your Core Layer of Survival/Self-Recovery (SSR) gear.
- Models small enough to include in your SSR Core Layer or Go Bag should be used alongside chemical disinfection for suspect water.
Gravity Filter – You fill a bladder container with suspect water and elevate it. Suspect water trickles down a hose to the filter by gravity.
Then treated water flows out of the filter via an output hose into a second bladder that is situated at a lower level.
- You can let gravity does the work if you have time.
- You can add whatever functionality you like to some models. This can make these one of the most flexible option available.
- Some models aren’t all they advertise and so they fall short.
In Line Filter – This type of filter can be installed in a water bottle or between a hydration bladder and the drinking tube. Some models now feature a bladder that can be pressurized via a bulb pump or bladders that connect directly to the filter body. It can be pressurized by squeezing the bladder or setting a rock on top of it.
Bottle Filter – Just what it sounds like, a filtered water bottle.
- Simple to use.
- Doesn’t take up extra space if you carry a water bottle.
- I’ve never seen a model I would buy because the water bottles are plastic.
- Most people need a filter with flexibility and when you add accessories, this form loses its appeal.
Mechanical Filters – Mechanical filters that achieve comparatively fast throughput using a manual pump mechanism. The input hose typically has a strainer, float to keep it off the bottom of the lake or stream, and can be use with a pre-filter to extend the life of the main element.
- Models that add a mechanical pump to an inline that can also be used as a gravity filter and attached to a bladder offer unsurpassed flexibility.
- Pump and accessories add bulk.