The Grayl GeoPress Water Purifier is a bottle based water filter that removes bacteria, viruses, and protozoa from contaminated backcountry and international water sources. It’s easy to use, portable, and safe to use by individuals for day hiking, fishing, or international travel when you don’t want to mess around with a more complicated hose, bladder, or pump-based water purifier. The Geopress also addresses two key issues that other bottle-based filters and purifiers don’t, which is knowing when to replace the filter element, and something called cross-contamination, which is when you accidentally re-contaminate the drinking vessel or water you’ve just purified. But before we get into that, let me walk you through the basics and show you how easy it is to use the GeoPress Water Purifier.
Specs at a Glance
- Removes: Protozoa, Bacteria, and Viruses
- Geopress purifies and filters 24 fl. oz. of water in 8 sec.
- Purifier (replaceable) cartridge is rated for 350 cycles (65 gal./250L); as press time reaches 25 sec. (or 3 years have elapsed since first use) it’s time to replace the cartridge
- Meets the EPA guide standard and protocol for testing microbiological water purifiers
- Filter medium: Electroabsorption/activated carbon
- Dry weight: 15.9 oz
- 10.4 x 5.6 x 3.4 inches
The GeoPress has an outer bottle and an inner bottle, with a filter at one end and a drinking spout with a screw-on top at the other. To use it, you pull the inner bottle out of the outer bottle, fill the outer bottle up with suspect water, and then push the inner bottle into the outer bottle like you would a french press. It takes some elbow grease (force) to push the inner bottle down, but doing so forces water through the purifier’s filter element, filling the inner bottle with purified water. To drink it, you can unscrew the cap at the top and sip from it. It’s really that easy.
The purifier’s filter element lasts for about 350 uses, depending on water quality. When new, it takes about 8 seconds to push the inner bottle with its attached purifier filter into the full outer bottle, containing suspect water. When the amount of time to perform this action takes longer than 35 seconds, you know its time to change the purifier filter, which unscrews with a twist of the wrist. Replacement purifier filter elements are sold separately for about 25 bucks each.
When filtering, you can loosen the top cap a 1/2 turn to let the air out of the inner bottle and make the pressing motion a little easier.
Once purified, clean water fills the inner bottle. You have the option to drink it immediately, carry it as you would with any water bottle, pour it into a separate bottle if you prefer to carry it that way, or share it with others.
Cross-contamination occurs when you accidentally contaminate the part of your purifier or filter system that you drink from. This can occur if you touch a drinking spout with hands that are wet from contaminated water or if the mouthpiece of your hydration bladder drops in the dirt. If you use a water filter like a Sawyer and you touch your lips to its bite valve, chances are pretty good that it’s been contaminated.
For example. I cringe when I see hikers carrying a sawyer screwed to the top of a water bottle and drink from it, because I know it’s probably been compromised. The only way to un-contaminate the drink spout is to sterilize it, by washing it with chlorinated water. Cross-contamination is one of the key reasons people still get sick on hikes even though they’re using a water filter or water purifier.
The Grayl GeoPress guards against cross-contamination because it has a screw top that covers the drinking spout. This is also the biggest difference between the GeoPress and its predecessor, Grayl’s Ultralight Water Purifier. As long as you keep that drinking spout away from unpurified water, you can safely drink from it or pour the bottle’s contents into other containers for consumption.
Comparable Bottle-based Water Filters and Purifiers
|Make / Model||Type||Weight||Capacity||Replaceable Filter/Purifier|
|Mizu V12 Vacuum Water Purifier Bottle||Purifier||15.4 oz||40 gallons||No|
|RapidPure Intrepid Water Purifier Bottle||Purifier||9.2 oz||25 gallons||yes|
|Lifestraw Flex Water Filter Bottle||Filter||1.7 oz||500 gallons||No|
|Katadyn BeFree Water Filter Bottle||Filter||2.3 oz||250 gallons||Yes|
|Lifestraw Go Water Filter Bottle||Filter||7.8 oz||264 gallons||Yes|
The Grayl GeoPress is a bottle-based water filter and purifier that’s ideal for removing bacteria, viruses, and protozoa from backcountry or international water sources. Weighing 15.9 ounces dry, it’s too low volume for general purpose backpacking where you probably want to process several liters of water at a time (since it can only purify 24 ounces at once). Instead, I’ve found it to be a great water treatment solution for outdoor recreational activities like day hiking or fishing where there’s plenty of water around so you don’t have to carry any and you can drink when you’re thirsty. The GeoPress is also simple enough for anyone to use casually without a lot of training, making it a valuable general-purpose solution for all the members of your family.
Disclosure: Grayl provided the author with a Geopress for this review.SectionHiker is reader-supported. We only make money if you purchase a product through our affiliate links. Help us continue to test and write unsponsored and independent gear reviews, beginner FAQs, and free hiking guides.