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Gear Review: GRAYL GEOPRESS Purifier ("Water Filter")

Over the years I’ve had the chance to use many different kinds of water filters.  Filters that you pump, filters that you squeeze and filters that you fill up and then let drip.  Even one that you stick in the water and suck on like a straw!  The GRAYL GEOPRESS Purifier is the the first one I’ve used that you operate just like an AeroPress or french press coffee maker, exactly as the name would lead you to believe.  GRAYL also makes some of the most impressive purity claims of any filter I’ve used!  If you want to learn more, read on.

Earlier this summer the folks at GRAYL asked me if I’d be interested in reviewing their product, no strings attached.  Always one to try something new, I said “Yes, absolutely!”  I had never heard of GRAYL before, so I had no idea what to expect.


When the product arrived in the mail from GRAYL Canada, I was surprised at the size of the device.  It’s taller than a typical Nalgene bottle, but slightly narrower in diameter.  It’s also surprisingly heavy, weighing in at almost one pound or 450g.  The second thing that struck me was the feel of the thing: it’s truly rugged; compared to my other filters, it’s built like a tank!  Unless you tried to drill a hole in it, there’s no way this puppy would spring a leak on you unexpectedly; sadly, I can’t say that about the water filter I use the most often.

This Is One Solid, Robust Product!

The GRAYL GEOPRESS Purifier is composed of three pieces: the main body cylinder, a screw top lid (which itself has a smaller screw top opening), and the piece which does the actual water filtering,  a cylindrical plunger that slides down into the main body just like the plunger on an AeroPress coffee maker or french press.

The Three Main Pieces

The way the filter works is quite simple: you pull the plunger out of the main body cylinder and fill the cylinder with the water to be filtered (from a lake, creek, stream, etc.).  There’s a max fill line indicated at about 750 ml on the cylinder.  Then you grab the plunger section (which has the actual filter/purifier mechanism built into it at the bottom) and physically push it into the water that you just collected.  The process of pushing the plunger into the water forces the water into the filter/purifier mechanism, and clean, ready to drink water then bubbles up inside the top of the plunger mechanism.  It takes about 30 seconds to push all the water through the filter/purifier.

Let’s put that 30 seconds into context: when you use a pump style filter, you pump for a couple of minutes until you have all the water you want.  With a squeeze bottle type filter, you have to repeatedly squeeze your bottle to get all the water out that you want filtered.  With a straw, you have to suck repeatedly to get the suction going, then keep sucking until you’ve had enough water.  With a gravity fed system, you have to hang up your filter and wait until all the water slowly works its way through the filter.

In other words, there is no “free lunch”; no matter what kind of filter that you’re using, you need to take some kind of physical action to start the filtering process (pump, squeeze, hang, or in the case of GRAYL, push), and then you have to wait (seconds or minutes).


The benefit of the GRAYL GEOPRESS Purifier is that you do the physical action all at once for 30 seconds, then you have a container full of water ready to go.  The downside is that, from what I found, it does take considerable effort to completely push all the water though though the filter with the plunger.  By considerable, I mean that I had to put most of my body weight onto the plunger to get it going.  It gets easier about ½ way though, but it’s still hard.  If I was a waif of a thing, I would probably be disinclined to use the device; it’s just that hard. 

That said, I need to mention two other important other advantages of the GRAYL GEOPRESS Purifier that tip the scales in its direction.  The GRAYL is not only a filter, getting rid of the typical bacteria and protozoa you find in backcountry water, but it’s also a purifier that removes harmful viruses like Hepatitis-A, E.Coli,  Salmonella and more!  These are the nasties that can contaminate drinking water in environments with dense human populations and/or poor or ineffective sanitation.  That can literally be a lifesaver for some travellers, or at least keep you out of a hospital.  Further, the GRAYL GEOPRESS Purifier also removes a variety of serious contaminants from water, such as heavy metals, micro-plastics and pesticides.  I have not used any other filter that has this ability! 

Ever the skeptic, I asked the company for product test results from an independent lab that would back up these claims, and a report was provided to me.  The name of the test lab was redacted, but with some creative “googlewhacking”, I was able to learn more.  The bottom line is that GRAYL really seems to have done their homework here and created a product you can count on.  

Lastly, it’s worth noting that the GRAYL GEOPRESS Purifier is rated to  filter about 250L (or 66 gal) of water before the filter needs to be replaced (replacements available on their website).  That seems less than what I’m used to, but this product is taking more out of the water than a simple filter, so I’d cut them some slack on this point. 

Looking Down, Inside the GRALY GEOPRESS

So what’s my final word?  For me personally, I think the GRAYL GEOPRESS Purifier is a valuable addition to my travel kit when exploring outside of Canada, where drinking the water might compromise my health.  It also makes a great emergency filter to have on hand in the event of some kind of natural disaster or other crisis.  I don’t see the GRAYL GEOPRESS Purifier as replacing my lightweight (albeit less robust), easy to squeeze water filter bag; it does the job for the kinds of water borne hazards that I find in Canadian back country settings, so I’m inclined to keep using it there.  If you’re the kind of person that is ultraconservative about their water, or only wants to purchase a single device, the GRAYL GEOPRESS Purifier may be the solution you need!

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