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Reviews > Water Treatment > Filters > Grayl GEOPRESS Purifier > Test Report by Michael Pearl


INITIAL REPORT - August 04, 2019
FIELD REPORT - November 05, 2019
LONG TERM REPORT - January 02, 2020


NAME: Mike Pearl
EMAIL: mikepearl36ATyahooDOTcom
AGE: 45
LOCATION: Hanover, New Hampshire, USA
HEIGHT: 5' 9" (1.75 m)
WEIGHT: 155 lb (70.30 kg)

I have a great appreciation for the outdoors and get out at every opportunity. I am a three-season, learning to be a four-season backpacker and year-round hiker. Currently, my trips are two to three days long as well as an annual week-long trip. I utilize the abundant trail shelters in my locale and pack a backup tarp-tent. I like to cover big distances while still taking in the views. I have lightweight leanings but function and reliability are the priority. I mostly travel woodland mountain terrain but enjoy hiking beautiful trails anywhere.



Manufacturer: Grayl IMAGE 1
Year of Manufacture: 2019
Manufacturer's Website:
MSRP: US$89.95

Listed Weight: 15.9 oz (450 g)
Measured Weight: 18 oz (515 g) *after filtering water
Listed Dimensions: 10.4 in x 3.4 in (26.5 cm x 8.6 cm) Height x Diameter
Measured Dimensions: 10.5 in x 3.5 in (26.7 cm x 8.9 cm)

Colors Available: Alpine White, Camo Black, Coyote Amber and Visibility Orange
Color Tested: Camo Black

Features / Details

Volume: 24 fl oz (710 ml)
Removes: 99.9% of viruses, bacteria and protozoa
Filters: particulates, chemicals and heavy metals
Replaceable filter cartridge with approximately 350 uses, 250 L (65 gal)
Flow Rate: 8 seconds per 24 oz (5 L per minute)
Durability: able to withstand 10 ft (3 m) drop onto concrete

Materials BPA-Free: Polypropylene #5, food-grade silicone, TPE, ABS food-grade plastic

Warranty: Every Grayl is accompanied by a ten year warranty covering workmanship and materials.

Testing Standards: Independently tested by certified laboratory to meet or exceed NSF protocol 42 and 53 for pathogen and chemical removal. Meets EPA Guide Standards and Protocol of testing microbiological water purifiers.

The Grayl Geopress is a water filtration, purification and water bottle all in one easy to use, hold and carry unit. I have used various water filtration methods. The Geopress is unique and a first time method for me. The merger of the two separate items, the water bottle and the water filter into one simplifies things and makes sense to me.


The Grayl Geopress arrived in what looked very much like a sturdy shoe box. Opening the box and seeing the Geopress the first thing that came to my mind was an insulated water bottle. Removing Geopress from the box it fit nicely in my hand. The area with the Grayl name surrounded by green is a textured non-slip grip material making my grasp around the bottle secure. On the side opposite of the grip pad a line is etched on the bottle indicating the water fill line. The lid has an easy to turn cap that covers the spout. The cap is held to the bottle by a flexible loop. There is also a carry handle on the lid that I can fit one or two fingers through comfortably. I think the handle would also work well for securing the Geopress to my pack. The lid unscrews revealing the inside of the clean water portion of the Geopress as well as the top of the filter cartridge.

The Geopress in basically made of four parts fitted together inline. The outer part is the "scoop" to hold the untreated (dirty) water. Inside the outer bottle is the filtered (clean) water reservoir or Inner Press. Attached to the bottom of the clean reservoir is the filter cartridge. The lid is the last component that screws onto the Inner Press making the clean water easy to drink and holding it inside for transport.

The purifier or filter cartridge does its thing using ion exchange and activated carbon. Inside the cartridge non-woven ceramic fibers block particulates and contain positively charged ions and powdered activated carbon. As water is pushed through the fibers ion exchange permanently binds pathogens while activated carbon absorbs chemicals, heavy metals, flavors and odors.

The Geopress seems like a well-designed and well-made water purification and carry system. It looks rugged and slick with simple yet effective features. Although I do not travel places where this might be a concern, I like that the filter removes viruses. It is also very nice that the filter cartridge is replaceable and the old ones are recyclable. Grayl is encouraging recycling of the used cartridges by offering customers discounts towards replacement filters. I applaud their efforts to reduce the use of one time plastic bottles and making a product that is recyclable. All in all the Geopress feels sturdy with strategically placed textures and grips. I think the really neat part of the Geopress is its three-in-one filter, store and drink design. But before I got to that I went through the instructions.


The Geopress works in four steps. IMAGE 2

1. Rotate and pull apart.

This required a small amount of effort. I firmly gripped the cap and the green grip pad on the bottle. Then with the twist and pull motion the two bottles slowly separated.

2. Fill with dirty water (up to the fill line).

I was still at home so I filled with tap water at the sink. An important point here though as with all filtering systems one must be very careful not to expose the clean portion of the system to untreated water. Untreated water should only ever go into the Outer Refill Scoop portion of the Geopress.

3. Twist the cap 1/2 a turn to allow air to vent. Press the Inner Press down onto the Outer Refill.

I didn't want to force it too hard for fear of damaging something. So the press took me about 18 seconds. Maybe as things "break-in" from use this will speed up. But honestly filtering this much water in under 30 seconds works fine by me.

4. Drink clean, purified water.

I dumped the first one just to rinse out the Geopress. The second one tasted just fine!

Care and Use IMAGE 3

- Do not use soap on purifier cartridge. Soap will damage purifier media.
- Wash Geopress (NOT purifier cartridge) by hand. Do not put any components in a dishwasher. The
Outer Refill, Inner Press and Drink-Through Cap can all be washed by hand with warm, soapy water.
- Long-term storage: thoroughly dry the Geopress. Perform one "dry press" by pressing Purifier into empty
(no water) Outer Refill. Dump out excess water and allow to air dry for two to four days. Hand wash all
other parts. Reassemble to create air tight seal for storage.
- The lifespan of a cartridge varies with the quality of the water sources; the clearer, the better. High levels
of silt or sediment will shorten the lifespan of the cartridge. As "press time" reaches ~25 seconds (or
three years have elapsed since first use) it's time to replace your cartridge.
- Stored under proper conditions, an unused (and airtight) cartridge has a shelf life of ten years.
- IMAGE 4On an airplane change in cabin pressure causes air to expand inside the Geopress. To prevent leaking while flying with Geopress have it completely empty or completely full.


- Use with freshwater only. No salt or brackish water, no other liquids.
- Do not expose/fill Inner Press with untreated water, cross contamination may occur. If this happens
wash with soapy water and rinse thoroughly.
- Always begin with the cleanest (least silty) water available.
- Purifier cartridges are designed to remove trace amounts of chemicals and heavy metals. Geopress
was NOT designed to protect against industrial disasters or toxic blue-green algae (cyanobacteria), etc.
- Protect the Geopress in freezing temperatures. Cartridges are not significantly degraded after one freeze,
thaw cycle. However do not use after three or more freeze, thaw cycles.
- Do not expose the Purifier Cartridge to water hotter than 120 F (50 C), it will harm purifier media. Do not
put the Geopress in the microwave.


So with all the reading out of the way I moved on to some hands on use. My first experience using the Geopress was smooth and easy. Well, after flexing a little muscle to pull the Geopress apart. It worked as described in the previous section without any mishap. I have only two other mentionable observations. When I would pause in pushing the inner vessel into the outer vessel it made air "puff" sounds. The other is that a small amount of water remains in the Outer Scoop after each filtering press. None of these things pose a problem or disadvantage that I am aware of. The one and only downside I see is the volume of water produced per press. I will need to fill the Geopress two to three times to process the amount of water I am usually carrying at a time. I will see if these points change or other things flush out while in use outdoors.


The Grayl Geopress is an interesting twist to providing safe drinking water. I like backpacking gear that can serve more than one purpose. The Geopress does just that with filtering, storing and drinking from one container. The Geopress design and construction are done well while use is quick and easy. The amount of water the Geopress provides per press means I will need to press several times at each water source. I am accustomed to throwing my intake line in the water and pumping till all bottles are full when with a group. Or my solo method of filling a 2 L (64 oz) bag and squeezing till one or both bottles are full. But as I spend time on the trail with the Geopress I hope to discover how this new method works for me.



Three day, two night backpack

Mounts Wildcats, Carters and Moriah Traverse - Pinkham Notch, New Hampshire
Distance and Elevation - 22 mi (35 km) from 780 to 4830 ft (238 to 1472 m)
Pack Weight - 25 lb (11 kg)
Temperature and Conditions - 40 to 75 F (4 to 24 C) Clear and calm to raining and windy

Three day, two night backpack

Mounts Jackson, Pierce and Hale - Crawford Notch, New Hampshire
Distance and Elevation - 18 mi (29 km) from 1900 to 4310 ft (579 to 1314 m)
Pack Weight - 25 lb (11 kg)
Temperature and Conditions - 38 to 70 F (3 to 21 C) Clear and sunny

Three day, two night backpack

New Hampshire Presidential Traverse - Randolph, New Hampshire
Distance and Elevation - 19.5 mi (31 km) from 1300 to 6288 ft (396 to 1917 m) for a cumulative gain of 10,600 ft (3231 m)
Pack Weight - 25 lb (11 kg)
Temperature and Conditions - 45 to 85 F (7 to 29 C) Clear and sunny with steady wind above treeline


The Geopress accompanied me on three great hikes during this phase of testing. The last one is for many in New Hampshire the grand feather in their backpacking cap. This hike links up the highest summits in the state over many above tree line alpine miles. It was definitely one of the best I have been on in the Northeast.

The Geopress served me well on each trip. It rides along in the water bottle holder on the side of my pack. I further secure the Geopress in this pocket by running a side compression strap through the finger loop on the cap. The one down side here is the Geopress has some "bruises" from bumping trees and rocks. These bruises are small scratches and discoloring where the bottle has been dinged. None of this wear has negatively impacted the Geopress's function or performance.

I typically carry two liters of water while hiking. The Geopress filters and holds 710 ml (24 fl oz) so I packed an additional 1.5 l (50 fl oz) water bottle. I would filter two Geopress volumes of water to fill the extra bottle. Then drink the remaining water in the Geopress and filter one more volume to carry. This seemed like extra steps initially but probably took less total time than other methods of filtering I've used. I find the outer container for collecting water easy to scoop, submerge or catch fall water with. Once or twice when I was really tired from pushing hard at the end of the day the Geopress was a little challenging. I found it uncomfortable to crouch or lean over the Geopress with sore legs. At this point almost anything requiring muscle hurts and even pushing down on the Geopress was a wee bit hard.

I like the seamlessness of pressing the filter and immediately drinking from the bottle. I guess it gives me the sensation of drinking directly from the water source. The water from the Geopress tastes great. There are no unusual tastes or odors. I do find that there is always a small amount of water left in the outer container after filtering. This doesn't negatively impact the function of the filter. It's just mildly annoying to carry water that I can't use.

After returning home I followed the instructions for storage preparation. This is an easy, low effort, chemical free process. There's no washing, scrubbing, soap or bleach. I especially like the no bleach part. Removing the Geopress from storage there were no smells or odors on any components. The water filtered smelled and tasted just as good as always.


Overall I have been happy using the Geopress as the prime objective of safe backcountry drinking water has been met. The Geopress is an easy to use and effective filter. Additionally it works nicely as a water bottle immediately after filtering. I need to fill and press the filter two to three times to meet my water carrying needs. However it is easy and fast enough that this is not a penalty against the Geopress. Throughout this phase of testing my experience with the Geopress has been positive. All parts and components continue to work well without issue. I look forward to using it in the next phase of testing.




Wrights Mountain - Bradford, Vermont
Distance and Elevation - 8 mi (13 km) from 1000 to 1822 ft (305 to 555 m)
Pack Weight - 12 lb (5 kg)
Temperature and Conditions - 45 F (7 C) sunny with winds at the summit

Boston Lot - Lebanon, New Hampshire
Distance and Elevation - 6 mi from 800 to 1100 ft (244 to 335 m)
Pack Weight - 10 lb (4.5 kg)
Temperature and Conditions - 20 F (-7 C) and windy


I made it out with the Geopress for two more day hikes during this test series. I was hiking with my family both occasions. I filled the Geopress at home and headed out. We carried only the Geopress between the four of us for water.

We quickly finished the first bottle off early on in our hikes. It's funny my kids always become very thirsty at every trail head. Even with my asking that they "tank up" before leaving home. The Geopress was a big plus here. We didn't have to carry extra water weight on our day hikes. I usually don't pack a water filter on short day hikes. I don't feel it's worth the extra weight or time to filter water on a shorter hike. We usually tough it out until we return home. But with the Geopress the filter is built into the water bottle and it filters fast.

We filtered two batches of water to share on each hike. Additionally there was no pressure to "tank up" because we could just filter and fill up as needed. My kids really liked this but I gulped down as much as I could out of habit. My kids also liked that they could filter without their arms or hands getting tired. My other two commonly used filters require pumping a handle or squeezing a bag.
The overnight temperatures began to visit the freezing point during the end of this phase of testing. I therefore didn't take the Geopress on any more overnight backpacks. Nor will I until the freezing nights have come to an end. The Geopress is just a little to bulky to sleep with inside my sleeping bag. And liquid water will only become more and more difficult to come by as winter progresses.


IMAGE 2The Grayl Geopress is an interesting twist on water filtration and storage. The two are merged together in one fast and easy to use system. The Geopress provided safe drinking water on every occasion I used it. Additionally it is just as easy to clean and store as it is to use. I have been very satisfied with my experience using the Geopress. I have not encountered any difficulties or problems with it. I have only one minor complaint and that is with the volume of water processed per filtering. At the end of testing the Geopress remains in good working condition. It has no odors, smells or stains on its inner container or filter. It did suffer some minor cosmetic bruises but I think it only enhances its "trail cred". I look forward to the return of warmer temperatures when I will carry the Grayl Geopress on my day hikes again.

This brings my Long-Term report and this test series to an end. I send a big thank you to Grayl and for making this test series possible.

This report was created with the Report Writer Version 1.5 Copyright 2020. All rights reserved.

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