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Reviews > Water Treatment > Filters > Grayl GEOPRESS Purifier > Test Report by Brian Hartman



NAME: Brian Hartman
EMAIL: bhart1426ATyahooDOT com
AGE: 50
LOCATION: Central Indiana
HEIGHT: 5' 9" (1.75 m)
WEIGHT: 150 lb (68.00 kg)

I have been backpacking for over 30 years throughout Indiana, Ohio, Kentucky and most recently in Western USA. In addition to backpacking I enjoy family camping with my wife and kids and being outdoors in general. I would describe myself as a mid weight backpacker. I use fairly light weight equipment and gear but still like to bring more than the bare essentials with me while on the trail.


August 10, 2019



Manufacturer: Grayl
Year of Manufacture: 2019
Manufacturer's Website:

Technical Specifications for Grayl Geopress Purifier
Materials: Polypropylene #5, food-grade silicone, TPE, ABS food-grade plastic.  BPA-free
Capacity: 24 oz (710 ml)
Flow rate: 8 seconds per 24 oz (5 liters/minute)
Uses Active technology: Ion exchange, ultra-powdered activated carbon
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
Filters: Particulates including silt and microplastics; activated carbon absorbs chemicals, pesticides, heavy metals, flavors, and odors
Testing standards: Independently tested by a certified laboratory to meet or exceed NSF protocol 42 and 53 for pathogen and chemical removal; meets the EPA Guide Standard and Protocol for testing microbiological water purifiers

Height: 10.4 in (26.5 cm)
Diameter at base: 3.4 in (8.6 cm)
Weight: 15.9 oz (450 g)
Measured weight: 16 oz (454 g)
Cartridge lifespan: 350 cycles (65 gal / 250 L)  When press time reaches 25 seconds (or if it's been three years since first use) then replace cartridge
Cartridge shelf life: 10 years
Durability: Can withstand a 10 ft (3 m) drop onto concrete when full of water
Geopress made in China; purifier cartridge made in USA
Available colors: Camo black, Alpine white, Coyote amber, Visibility orange
Warranty: 10 years
MSRP: USA $89.95



Unrivaled ease, speed, and versatility: purifies and filters contaminated water in 8 seconds
Removes waterborne pathogens and filters particulates, chemicals, pesticides, and heavy metals
Improves taste, smell, and clarity of water
SimpleVent drink cap vents air while purifying, protects against cross contamination, and allows one-handed hydration via drink spout
SoftPress comfort pads allow for non-slip, anti-fatigued pressing
TopoGrip non-slip TPE is used on all heavy use surfaces
Saves money and prevents waste by reusing container versus single-use bottled water

The Grayl Geopress Purifier (hereafter called Geopress) is an intriguing new water purifier, made by Grayl, a Seattle based company that got their start on Kickstarter.  The Geopress has four parts as seen in the photo to the right: 1) the lid, which includes a carrying handle and the SimpleVent cap 2) the Inner Press, which holds purified water 3) the cartridge, which purifies dirty water and 4) the Outer Refill container, which holds dirty water.   The lid screws onto the top of the Inner Press and the cartridge screws onto the bottom of it.


The Geopress arrived at my doorstep in a nice display box that looked like a small shoe box.  Upon opening the box, I found the Geopress to be in excellent condition, with no marks, scratches or defects whatsoever.  My first impression was that it was bigger than I expected, given its 24 oz (710 ml) water capacity.  However, the large size makes perfect sense considering this is a complete system that includes a water bottle, purifier cartridge, and dirty water container all in one unit.  In fact, I really like that the Geopress is all together.  It makes it simpler to carry and use, as compared to systems that have 12 different components, including hoses and valves that fit together, pumps, gravity bags, and multiple filters; all things that must be kept track of and cleaned etc.  With the Geopress, everything is together, in one place, and using it is as easy as 1, 2, 3 (more on this later).  There are no small items to lose and because there is only one moving part, it is easy to prevent cross contamination.  In addition to being a big fan of the design, I like its color scheme and am impressed with its build quality.  This is one rugged water purifier!  Just holding it in my hands I can tell it's made for the outdoors.  The materials are strong and beefy, not cheap and brittle.  The Outer Refill has a non-slip base and a high-water mark that indicates the maximum fill level of the container.  Similarly, the Inner Press and cartridge feel rugged and appear to have quality seals.  The handle on the lid is a nice touch as well as the strap that prevents the SimpleVent cap from getting lost.

Of course, the Geopress is first and foremost a water purifier, and as such, it has some pretty impressive specs.  It removes 99.99% of viruses, 99.9999% of bacteria, and 99.99%o of protozoan cysts.  All nasty stuff.  In addition, it filters out particulates, chemicals like chlorine, benzene, and chloroform, and heavy metals like lead, arsenic, and chromium.  This is one badass water purifier.  The cartridge has a great lifespan as detailed further down in my report, and every time I use the Geopress I keep a plastic bottle out of the landfills.  What's not to love about that.

The Geopress is 10.4 in (26.5 cm) tall and 3.4 in (8.6 cm) wide at the base.  The cartridge is orange in color, 3 in (7.6 cm) in diameter, and approximately 2 in (5 cm) tall.  It has a threaded piece on top that allows it to screw into the Inner Press.  

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A multi-fold color pamphlet was included with the Geopress and it provided lots of useful information about the product.  Moving on to how this thing works, using the Geopress purifier couldn't be easier, as there are only four steps to getting clean, safe drinking water:  First, grab the lid with one hand and the Outer Refill container with the other, and pull them apart.  It may help to twist or rotate one hand while pulling with the other to help separate the two parts.  Second, fill the Outer Refill container with dirty water.  Note there is a maximum fill line on the Outer Refill.  Third, open the SimpleVent cap to allow air to escape and press down on the lid/Inner Press.  Dirty water will be filtered through the cartridge into the Inner Press.  It takes roughly 8 seconds to filter a full container of water.  And fourth, drink away.  That's it.  

Care and cleaning the Geopress is straight forward.  Wash the Outer Refill, Inner Press, and lid/cap with warm, soapy water.  Do not put any items in the dishwasher.  Don't wash the purifier cartridge with soap or any cleaning products because it will damage the filter media.  Thoroughly dry the cartridge before storing to prevent mildew.  Dry by pressing the wet cartridge into the empty Outer Refill container, then allow the cartridge to air-dry for several days.  Finally, reassemble the unit to create an airtight seal.  The lifespan of the purifier cartridge is approximately 350 cycles, which equals 65 gallons (250 L) of water.  When it starts taking 25 seconds or more to press the Inner Press and Outer Refill containers together then it is time to change the cartridge.  Of course, don't let the cartridges freeze or expose them to hot or boiling water.  Finally, don't try to purify saltwater or any other liquids besides water.

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In order to test the Geopress, I took it into my backyard and filled the Outer Refill with water from my garden hose.  Then I pressed on the top of the Inner Press until all the water was purified.  I was a little surprised at how much force was required to filter the water, although the process was quick (I counted 10 seconds) and not difficult to do.  If asked what I like most about the Geopress, my answer would be its simplicity.  Fill.  Press.  Drink.  No wait time and bad taste as experienced with Iodine tablets, no stirring water and hoping for the best as is the case with my UV stick, and no complex filter system that I may or may not have cross contaminated when swapping hoses and valves.  The Geopress is simple, and that's what I like most about it.  


The Grayl Geopress Purifier is lightweight, well made, and durable.  I love its design and am excited to get it into the field for testing.


November 4, 2019



During this test period I went on a three week backpacking trip through Europe that included nine different countries.  I was so glad I took the Geopress with me as it was quick to use, and I was able to drink water wherever I was at without worrying about getting sick.  Below are a few of the places I used the water purifier:

Location: Venice, Italy
Stay: 2 days, 2 nights
Weather: 68 to 80 F (20 to 26 C) with partly cloudy skies the first day and clear blue skies on day two
Interesting fact: There are 122 public water fountains in Venice, including this one near Piazzale Roma (photo right), and Venice authorities tout them as safe to drink from.  With that said, I filtered all the water I drank in Venice.  Not that I didn't trust the water source (well maybe I had a few questions because of Venice's sewage problems) but the Geopress was very easy to use and it doubled as my water bottle throughout Europe.

Location: Rome, Italy
Stay: 3 days, 2 nights
Weather: 71 to 82 F (21 C to 27 C).  Sunny and warm all three days.
Interesting fact: Rome has over 2,500 public fountains, called nasoni, within the city limits.  Most of them are in the historic district, where water is brought in via the same aqueducts that were built by the Romans starting in 312 BC.  

Location: Budapest, Hungary
Stay: 1 day, 1 night
Weather:  68 to 76 F (20 to 24 C).  It rained the first night but dried out the following morning.  The next day was mild and overcast.  
Interesting fact: Budapest has more thermal springs than any other capital city in the world.  18 million gallons (70 million liters) of water rise to the 
surface daily.  

Location: Durnstein, Austria
Trip Three: 1 dayspot
Weather:  65 F (18 C).  Cold, overcast, and very windy.
Interesting fact: Durnstein is considered by many to be the most beautiful village in Austria.  It sits on the Danube River, which is the second longest river in Europe.  The Danube flows through ten countries, more than any other river in the world.

Location: Hallstatt, Austria
Trip Three: 1 day, 1 night
Weather:  66 to 72 F (19 to 22 C).  It was raining when I arrived, but an hour later the rain stopped and that's when I made the hike up to Hallstatt's famous salt mine.
Interesting fact: Hallstatt is home to the oldest salt mine in the world, dating back 7,000 years.  It is also considered to be one of the oldest still-inhabited settlements in Europe.

Location: Karlstejn, Czech Republic
Trip Three: 2 days, 1 night
Weather:  71 to 74 F (21 to 23 C).  Sunny and mild conditions.
Comments: Beer is about 90 - 95% water and the Czech Republic is the #1 beer-drinking country in Europe.

Location: Barcelona, Spain
Trip Three: 2 days, 2 nights
Weather:  75 to 84 F (23 to 29 C).  The weather in Barcelona was warm in the mornings and hot in the afternoons with sunny skies both days while I was visiting.
Comments: All seven of Barcelona's beaches were man-made, in preparation for the 1992 Olympic games.  
Interestingly, Barcelona is ranked 2nd on the list of best beach cities in all the world.  


During Field Testing I hiked over 170 mi (274 km) throughout Europe and the Geopress was with me every step of the way.  Although it wasn't lightweight, it was incredibly easy to use and doubled as a water bottle.  The photo above is of the Grand Canal in Venice and the two photos below were taken while hiking up to the Karlstejn Castle in the Czech Republic.  The castle was built in 1348 and is located about 20 mi (32 km) southwest of Prague at an elevation of 1,132 ft (345 m).  The hike from town to the castle took approximately 40 minutes and included several scenic views of the surrounding countryside with a great sneak peak of the castle from a nearby hill near the end of the hike.    


I had no problems with water spilling out of the Geopress until my flight from Rome to Budapest.  After getting on the airplane I loosened the top cap on the Geopress, stowed it in my pack, and then wedged the pack upright underneath my seat before takeoff.  Upon landing I found my pack and everything in it was soaking wet.  Air pressure changes may have been a factor but then again, the cap was loose so I suspect the Geopress tipped over in my pack.  Regardless, my electronics and other essentials were fine since they were sealed in a bag within the pack, so my pack and clothes were the only things that got wet, and I was able to dry them out using a hand dryer in the airport restroom.

As luck would have it, I had another spill an hour later, but this time it wasn't a mystery.  Before leaving the Budapest airport I stopped in the lounge for a quick bite to eat.  While there I refilled the Geopress by unscrewing the top lid and pouring in two bottled waters.  What I didn't realize until shortly afterwards was the water was carbonated.  Since the cap was tight, pressure built up until water leaked past the seal and soaked my pack.    

IMAGE 4The Geopress was plenty durable on my trip.  On several occasions it fell from where I set it, on a table, rock or ledge, but it never cracked or showed a hint of being damaged.  It also had plenty of capacity for my needs.  Whenever water was available to filter, I filled the Geopress, drank as much as I wanted, then refilled the container again.  That way, I always started every hike with a full container of water.

I don't know what contaminants, if any, were in the water I collected while in Europe, but I strived to pick good water sources whenever possible.  That meant not collecting water from ponds or puddles or anywhere where there wasn't inflow or outflow.  It also meant not collecting water from fast moving streams or waterfalls where there could be suspended particles.  Third, I avoided streams that flowed through cultivated fields, because they might contain fertilizer, herbicides, and/or pesticides.  Finally, I avoided water that smelled bad or was red or orange colored.

Throughout my trip the Geopress produced crystal clear water that had no odor and no taste.  I felt very confident that the water I was drinking was purified.  The first time I pressed down on the Geopress I was able to filter a full container of water in 8 seconds.  I noticed that by the end of my trip it took closer to 12 seconds to filter the same amount of water.  

Here are a few observations I made while using the Geopress during the past two months: 

1. The quality of the water produced was excellent.  

2. The Geopress was easy to use and carry, although it wasn't lightweight or small, compared to straw filters etc.  

3. The Geopress was reliable.  I took it everywhere I went and used it multiple times a day, every day and it just worked.  One note is that the Geopress is not intended to be used when temperatures are consistently below freezing as the filter will be damaged if water freezes inside it. 

3. The Geopress was rugged.  It fell multiple times onto concrete and continued to work.

After returning from my backpacking trip I emptied the Geopress then pressed down on it to evacuate any water that remained in the cartridge. Next, I washed out the outer press and let everything air dry.


What I like best about the Geopress is how easy it is to use.  It's one of the simplest water purifiers I've used.  There are no hoses to connect, no filters to screw together, no bags to hang, and I don't have to lay on the ground and suck water through a straw.  Instead I simply scoop up some water, press down, then drink.  

This concludes my Field Report for the Geopress.    



December 31, 2019


During this test period I took the Geopress water purifier on multi-day trips to NE Wisconsin and N Ohio as well as on an overnight trip to S Indiana.  I hiked approximately 26 mi (42 km) over an eight-day period and it performed flawlessly.  Below are details on these three trips:

Location: Mayfield and Hudson, Ohio
Stay: 3 days, 3 nights
Weather: 22 to 35 F (-5.5 to 2 C) with cloudy skies the first two days and clear skies on day three
While in N Ohio I hiked in the Cleveland Metro Parks as well as the Cuyahoga Valley area.  

Location: Francis Creek, Wisconsin
Stay: 3 days, 3 nights
Weather: 25 to 36 F (-4 C to 2 C) with mist and occasional rain the first two days and clear skies on the third day.
While in Wisconsin I spent most of my time on and around the Devil's River Trail.  It's open to hikers and bicycles in summer and cross-country skiing, snowshoeing, and snowmobiling in winter, although I rarely see anyone.   

Location: Franklin County, Indiana
Stay: Overnight
Weather: 34 to 38 F (1 to 3 C) with light winds and mostly clear skies


First off, the Geopress didn't leak any water during Long Term Testing.  That was good news given the two incidents that occurred during Field Testing in Europe.  Because I experienced no problems during the past two months of use, I believe the issues in Europe were isolated and am confident the seal and cartridge are functioning properly.     

The Geopress performed wonderfully during Long Term Testing.  It was quick and easy to use.  While testing this item I found I was able to filter water in half the time it previously took me.  I typically filtered 48 oz (710 ml) of water while stopped, enough to fill the Geopress and a second plastic bottle.  I collected water from many sources in Wisconsin, Ohio, and Indiana, including the pond below.  Although ponds aren't my first choice for water, I felt safe with the Geopress given the technical specs on their cartridge.  It has consistently produced excellent drinking water with no after taste or odors.  Back to my trip, since the pond appeared to be the only source of water available in the area, I set up camp on a ridge within eyesight of it.    

I commented during Field Testing that the Geopress was plenty durable.  After two more months on the trail I stand by that statement.  I'm careful with the Geopress but I certainly don't baby it.  It's had more than its share of drops, falls, and accidental kicks with only a few scratches to show for it.  And it still performs with no issues.  In my mind, it's completely reliable and should last indefinitely, as long as the cartridge doesn't freeze. 

Grayl offers three methods to determine the useable life of a cartridge.  The methods are based on 1) quantity of water, 2) number of presses/cycles, and 3) press time.  Using the first method, during Long Term Testing I filtered approximately 7.5 qt (7 l) of water, bringing the total quantity of water I filtered during the past four months to 40.5 qt (54 l).  This calculates to about 1/5th of the cartridge lifespan which Grayl lists as 65 gal (250 l).  Using the second method, I performed the press operation approximately 58 times during testing and Grayl lists the total number of presses/cycles that can be achieved per cartridge at 350.  So based on press cycles, my cartridge is at about 1/6th its useful lifespan.  Finally, the last few times I filtered water it took 12-14 seconds for me to complete the press operation and Grayl recommends replacing the cartridge when the press time reaches 25 seconds.  Using this method, the cartridge is presumably 1/4th of the way through its useful life, assuming press time rises linearly throughout the cartridge's lifespan.  I like that there are multiple methods to determine the life of the cartridge, even if they don't agree 100%.  

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My favorite thing about the Geopress is its simplicity.  It's one of the easiest water purifiers I've used thus far.  Granted, it's larger and heavier than many other filtering systems, but what could be simpler than scooping up water, pressing down on the Geopress, and drinking.  For the times when I'm solo backpacking and temperatures aren't consistently below freezing, this is my new favorite system.

This concludes my Long Term Report for the Geopress and this test series.  Thanks to Grayl and for allowing me to participate in this test.    

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