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Reviews > Water Treatment > Filters > Grayl GEOPRESS Purifier > Test Report by David Wilkes

Test series by David Wilkes

GRAYL Geopress Purifier

Initial Report - August 6 2019
Field Report - November 17 2019
Long Term Report - February 9 2019

Tester Information

Name: David Wilkes
Age: 52
Location: Yakima Washington USA
Gender: M
Height: 5'11" (1.80 m)
Weight: 210 lb (90.7 kg)


I started backpacking in 1995 when I moved to Washington State. Since then, I have backpacked in all seasons and conditions the Northwest has to offer.  I prefer trips on rugged trails with plenty of elevation gain. While I continuously strive to lighten my load, comfort and safety are most important to me. I have finally managed to get my basic cold weather pack weight, not including consumables, to under 30 lb (14 kg).

Product Information



Year of Manufacture:


Manufacturer’s Website:


$89.95 USD

Listed Dimensions:

Height: 10.4" (26.5 cm)
Diameter (at base): 3.4" (8.6 cm)
[varified by tester]


Listed: 15.9 oz (450 g)
Measured 16.65 oz (472 g)


24 oz (710 ml)
[see note in report]

Product Image
Product Image

Product Description:

The Geopress Purifier from Grayl is a rather ingenious combination of water filter and bottle that operates very much like the French press style of coffee makers. It filters out particulate material (dirt, sediment, etc.), removes chemicals and waterborne pathogens (viruses, bacteria, protozoan cysts). It can also improve the smell and taste of the water.

It is available in 4 colors: Alpine White, Camo Black, Coyote Amber, and Visibility Orange (I received the Orange).

Initial Report

August 6 2019

PartsThe Grayl Geopress Purifier looks similar to a large size water bottle. It has a small drink opening with screw off cap (with retention strap), and the entire top can be screwed off. The lid also has a loop that can be used to secure the bottle, such as to a pack strap or a carabiner. The outer shell of the Geopress is textured and has a "TopoGrip” section to improve grip. The outer shell is removed for water collection and then the inner bottle/filter is inserted into the shell and pressed down to force the collected water through the filter and into the inner bottle. The inner bottle is a slightly opaque white plastic and the filter connects to the bottom with a quarter turn bayonet style connection. There are flexible seals around the filter and at the top of the bottle to ensure a good seal and prevent leakage.

The filter cartridge is removable and replaceable. It is rated for about 350 cycles (65 gal / 250L) and “Removes waterborne pathogens (99.99% of viruses, 99.9999% of bacteria, 99.99% of protozoan cysts), including Rotavirus, Hepatitis A, Norovirus, Giardiasis, Cryptosporidium, E. Coli, Cholera, Salmonella, Dysentery and more”. Like all other filters I have used, there are warnings that allowing the filter to freeze can damage it.

The bottle is somewhat larger and heavier than I had anticipated, but being an all in one filter and bottle this is to be expected. For reference the bottle is about the same size as a 32oz (1L) water bottle and when full about the same weight, but the Geopress holds 24oz (710ml) of water (see note below). All of the exterior surfaces of the product have a textured surface giving it a feel of quality construction. The lid includes rubber like surfaces to assist in making pressing down on the lid while filtering more comfortable and less likely for my hands to slip. The drinking lid is easy to remove and large enough to allow for guzzling water if desired. The entire lid can be screwed off to allow full access to the drinking bottle (cleaning, adding ice, etc.).

Upon receiving the product I disassembled it and inspected it for flaws or defects (found none) and reassembled, then filled the outer shell with tap water and inserted the inner bottle/filter. I was expecting the filtering to take some force but was still a bit surprised at how much. But in seeing how quickly it filtered the water (<30seconds) I believe the amount of force needed compared with the flow rate seems reasonable. For reference I have other filters that take far less force but also operate at a much lower rate. It seems the overall effort it takes is about equal. (effort = force X time) As my tap water has a slight but noticeable taste of chlorine I performed a taste test of unfiltered tap water vs the water out of this filter and the chlorine taste was noticeably absent from the filtered water.

NOTE: the listed capacity of the filter is 24 oz (710 ml). I filled the outer shell to the full line, filtered it, and measured what was in the inner bottle and got 22oz (650 ml) and I found the inner bottle could hold about 26 oz (769 ml).

One thing I immediately considered upon receiving this product is that its simplicity and all-in-one design seems like a good option for outings where carrying large volumes of water are not necessary, and since I really don’t like carrying any more water than I need this seems like a good design. For other outings this would require filtering the water one batch at a time and then transferring to a separate container(s). But since this is in essence what most common water filters do anyway this may sound worse than it really is in practice. I guess I will find out during the testing.

I would note that I have used at least 5-6 different make/models water filters over the years. While much of the water in the areas I frequent is probably perfectly safe to drink, Giardiasis & Cryptosporidium has been found in some of the local water and of course there is no way to really know what is going on upstream so I prefer to not take chances and filter or boil any water I plan to consume. Another factor is much of the water I collect tends to be from streams and lakes where the amount of grit, sediment, and general ‘floaties’ (e.g. bugs and stuff) can be rather high and I have had filters clog on me. As such my preference is for filters that can be serviced (back flushed) in the field (this does not seem to be an option with the Geopress). I would also like to mention that I have tried chemical and ultraviolet treatments but am not a fan of those, so I stick to filters.

A final note is that depending on the outing I tend to switch back and forth between water bottles and a hydration pack, but for any outing more than a couple hours (and not in sub-freezing temperatures) I tend to favor a hydration pack and have mine set up so that I can filter water directly into my hydration pack without having to remove it from my backpack. Obviously if I am going to fill a hydration bag using the Geopress I will have to remove it from my pack first.

My first impression is that this is a well-made product that is fast and easy to use. It seems a bit bulky/heavy compared to what I normally prefer for backpacking but seems like it might be well suited for day hikes, general outings and travel.

Likes: Innovative product, all in one bottle/filter, easy to use and fast, good for frequent/fast water collection
Dislikes: No field service (backflush) option, filtering volume per filter rather low, can't directly fill my hydration bag

Field Report

November 17 2019
Sand LakeUse:
  • Day Hike x3 -  Sand Lake – Washington Cascades ~5mi / ~8km
  • Day Hike x2 – Pacific Crest trail maintenance scouting, Central Washington  Cascades ~8mi / 13km
  • Day Hike – White Pass Ski resort

With the exemption of the last trip (White Pass Ski resort) I carried this filter and a second water bottle. I started out each trip with a full 0.5L (16oz) water bottle. I would start out by drinking from my water bottle, then use the Geopress to filter water which I would transfer to the water bottle. Then I would fill the Geopress and carry it full, drinking from both along the way. On the two Sand Lake trips I also used it to filter water which I poured into my dog's trail bowl for her to drink. The water sources were streams and lakes. On the last trip, knowing the weather would be on the cold side (near freezing) I filled the Geopress at home and refilled it once from a small stream (snow melt) along the way.

So far all of my use of this filter has been for day hiking. I have wanted to take it with me backpackign but the size, weight and volume simply does not work with my equipment, so I have not been able to bring myself to pack it for backpacking trips (my backpacking water filter weighs 1/8 as much as the Geopress).

For day hiking along trails I know will have water I really love the Geopress. I hate to carry any more water than I need and so the Geopress allows me to quickly refill at any and every water source I pass. From the viewpoint of speed and convenience, I have to say I have not used any system that is better. When I reach a water source I can quickly pull out the Geopress, fill it, filter (takes seconds) and be on my way. Filling another bottle is also quick and easy. I estimate I can get a water bottle and the Geopress filled in less time than it takes to even set up other filter systems I have used. The filter does take considerable pressure to operate but the design makes that quite easy, as I simply place the Geopress filled with source water on a hard surface (log, ground, rock, etc) and push down. I have yet to find a situation where this is a problem.

I would mention one possible side effect to filling my water so often and that would be more opportunities to view local wildlife. On one hike, as I reached the edge of a lake to refill I saw a snake just off to my left and then something shot past my right foot. Saying I was startled would be a huge understatement (the language that escaped my mouth is not printable here). I was then quite embarrassed to find it was only a frog, and the snake just a harmless Garter. At the next lake I encountered a number of salamanders.

Talus SlopeSo far I am really impressed at the speed and convenience of the Geopress, and find it just about ideal for my water needs when on day hikes where I am likely to encounter water sources along the way. I also like the large drink opening, allowing me to guzzle or sip from it as I please.
I am less impressed with the overall size, weight and bulk, but only in the context of if I would want to carry it backpacking.Snake

Long Term Report

January 14 2019
Since the Field Report I have only used the Geopress once and it was for a 5 day trip to Los Cabos Mexico. I carried the bottle for use in the airports and on the airplane, filling it twice (once in Seattle and once in Los Angeles). I also used it 3-4 times while in the resort to filter tap water in our room.

While traveling I was able to avoid the cost and waste of purchasing bottled water, allowing me to give no thought to the quality or taste of the airport drinking water and I doubt I have to say how nice it was to be able to filter and drink the tap water at the resort without any concern over the water quality there.

While I found the product to be too bulky and heavy for backpacking, it is a really quite convenient for day hikes reducing the amount of water I need to carry and allowing me to hydrate more often. But for me I think the real value of this product, and where I expect to continue using it, is for traveling, especially when going out of the country.

This concludes my Report.
I would like to thank the folks at GRAYL
and for the opportunity to test this product.


Read more reviews of Grayl gear
Read more gear reviews by David Wilkes

Reviews > Water Treatment > Filters > Grayl GEOPRESS Purifier > Test Report by David Wilkes

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