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Looking for a water purifier for back packing, does anyone have experience with a Grayl Geopress?

I am looking For a water purifier. I am new to backpacking. I have been looking at the Grayl Geopress, but as I shop in places that specialize in hiking equip and talk to some people who I know to have extensive experience in hiking, have never heard of Grayl. Is that because it is more of an international product and not just a back packing item? What is my best option as a water purifier for light back packing?I would like to do some longer hikes, so I want to invest in decent equipment but it can be confusing.

13 Replies

Hey @beckyt!

Thanks for reaching out! We're excited to hear you're getting in to backpacking. I haven't used the Grayl Geopress personally, but I've seen it used and it is pretty slick. They're a relatively new company to REI (just a couple of years) so that may be why you've never heard of them. The technology seems to work great though, it's a cool way to make your water potable.

A quick question: were you looking specifically for a water purifier, or were you looking for a water filter? A lot of folks think they need a purifier but actually really only need a filter, and the difference can save you a good amount of money if you don't actually need a purifier. Take a look at this Expert Advice article, How to choose a water filter or purifier, it's got a lot of really good info. Then come back an ask any questions you may have, we'll be ready!

Hopefully this helps, thanks!

At REI, we believe time outside is fundamental to a life well lived.

If you are hiking in the US generally you do not need to worry about water born viruses, only bacteria and protozoa.  The Sawyer Squeeze...

and the Katadyn BeFree are popular choices.

The BeFree probably is less prone to clogging but it can't be backflushed like the Sawyer.  Also the Saywer Mini and Micro tend to clog faster and have a slower flow rate so the Squeeze is preferred.

I use a Squeeze along with CNOC VECTRO bag and other modifications to make it gravity fed.   I prefer a PVC tube other the one Sawyer provides in the set linked because it can rotate on the barb.

and camco hose filters to keep the larger particles out of the filter

The Squeeze threads are compatible with many disposable water bottles in the US.  Some people place the Squeeze directly on the bottle and drink from the filter directly.   The SMART and LIFE 1 liter bottles are preferred by many for being both robust and a convenient shape plus you can get them with sport caps.  You replace the bottles as needed.   This does not work so well internationally since different thread standards are more common on disposable bottles.

I generally carry 2* 1L and 1* 0.5L SMART or LIFE bottles and fill them according to where the next reliable water source is.  I usually carry a backup flat bottle in case a dry camp beckons but I have never actually used it.

I do not recommend just using the flat bottles that often come with the Squeeze except for occasional backup water storage for when you want to dry camp for example.  They are light and pack small but they are pretty much useless for collecting water and they tend to split.  

In addition to the filter it is a good idea to carry a backup such as the aquamira drops

or PUR tablets.

They take time to work (up to 4 hours for crypto)  and are best used with a filter as above since they will remove the cryto.  This covers you in case your filter breaks or the water source is particularly nasty and you suspect virus contamination is possible. 

You can also use your stove as backup.  Some people prefer it as a primary method since heat is a more certain method but in my view it is not a very convenient for every day.  It won't filter out particulates and there is setup and fuel cost to consider.   The EPA recommends boiling for at least 1 min at sea level increasing the time to 3 mins above 5000ft.  Some people claim you only need to "pasteurize" it by it getting it to ~70 degrees C (I think) but I don't trust that personally.  Pasteurization is designed to not spoil the flavor or milk not purify water...safer just to boil as recommended rather than risk warming water and multiplying the nasties.

There are other filter choices that have carbon elements like the Katadyn Hiker and that might be a better choice in areas that have agricultural run off since the carbon filter will remove some of the chemical contaminants or at least improve the flavor.

I have one used to use it but where I hike that is not a issue and the Sawyer set up is much lighter and the replacement filters are expensive.

For group use the Platypus Gravity is nice (I have one) but again the filters are expensive...(has a carbon element also) , the threads are proprietary and the whole thing is quite heavy and bulky.

I took a quick look around at the Grayl Geopress and my general impression is that it is a good choice for international travel (viruses + do you trust the tap water) and extended dayhikes in places there is water you can filter so you don't have to carry as much.  Its probably not the the best choice for wilderness backpacking in the US.  1. It is heavy, 2. It is slow. 3.  It is bulky. 4. Replacement filters are quite expensive and last 350 uses or 3 years whichever is sooner...something you have to keep track of in gear that you store. 5.  It filters more than you generally need in the US so it's inconveniences are not justified.


@beckyt (35 years experience, soloist and survivalist, here)

@REI-JohnJis correct, as I've said for years, there's a difference between a water filter and a water purifier! In "first world" countries (US, UK, etc.) you really only need a water filter. Here in the US, our backcountry waters are fairly clean. If you go to "third world" countries, you'll probably be better off with a water purifier (for detailed information, see my previous post/thread: "TREATING WILD WATER"

I actually saw the Geopress' predecessor YEARS ago (long before their 2019 kickstarter), and it was impressive then. I don't know if this is the SAME product, but suffice to say  it's not a new idea/approach. However, at almost 00, you may want to wait for more people to use it and check the reviews of people who have ACTUALLY USED it for a while.

In the meantime, while there are several good water filters, but I personally have used Sawyer filters (first the Mini, now the Micro) for maybe 10 years now and highly recommend it. If you choose one of these, I have two caviates:

First, do NOT use the bags that come with the Sawyer, they are C***!! Get a CNOC bag!!! (preferably the larger one). Second, I'm reminded of a VERY accomplished distance hiker (Darwin) who stopped using his Sawyer MICRO because of flow rate issues.

I told him I have no such problem, however I use a CNOC bag. And because it's a kind of rubber, I usually just sit on it and let my body weight push the water through. Also, I essentially "backwash" the filter after each use. I attach the Sawyer to the CNOC, but on the other end of the Sawyer, I attached a rubber tube (which allows me to use it like a Lifestraw) so I just swing it around and let it backwash with centrifugal force. PRO TIP: it works better if the filter [membranes] are already wet/moist.


Never heard of it.

lots of reading here.

I’m currently using a sawyer, can alternate between a smart water bottle and a 3liter bladder.

don’t forget to take the back flush syringe.

please let us know what you select.

good luck


REI Member Since 1979

I used to use a water bladder in my pack, but whether it was a Camelback or a bladder in my pack, I NEVER liked the feeling of having a barrel strapped to my back! To say nothing of having to tighten my pack straps to compensate for my gear shifting around when the bladder got low!! Now I use water bottles instead of a bladder.

I use several Fiji Water bottles. MUCH better than any round Smart Water bottle or the like! For one, they are made  from P.E.T. plastic (recommended for "solarizing" water, in a pinch!), they're also thicker so less likely to fail. Not to mention they're square-ish, so less likely to roll away from you if you set them down.

And, empty water bottles won't make your gear shift around in your pack as you drink the water. How do I get at the water while I'm hiking if it in my pack? As always, glad you asked...

I bought a rubber tube, and used half with my Sawyer-CNOC setup. The I bought a mouthpiece and a small rubber gasket and with the other half of the rubber tube, made my own "bladder" drinking system. Works BRILLIANTLY!!!


FYI Almost all disposable water bottles are made of PET aka PETE. SMART and LIFE water bottles certainly are. They are thicker than most common bottled water brand bottles which is why they are popular with Sawyer using backpackers. There are a few other brand bottles that also use thicker PET. Fiji apparently uses rPET which is currently PET + 20% recycled PET but they hope to increase to 100% in the next few years. I haven't tried them but and I can see the squareness having an appeal. PET make good water containers because it does not impart a taste or absorb odors. Plus disposable bottles are essentially given away.  The main problem with PET is that is only good to 130F which means no hot liquids and probably not the best choice for the hottest day recorded ever the other day in Death Valley.

I agree about hydration bladders.  They are great for extended day hikes or athletic activities where water is the main weight you are carrying.  But for general backpacking I just find them inconvenient and I don't like the risk of them failing or leaking inside my pack.  Their one big advantage is they can't fall off your pack but for me disposable bottles make more sense for general use.  My backpack has a bottle holster I can get to when hiking so I just use a sport cap.  

As I said above I also use a CNOC Vectro to gather water and to extend carry capacity if called for.   Since it is a dirty water bag  I don't drink from it or use it to backflush my filter.   I guess I don't really understand what you are doing there.


(I feel like I'm repeating myself! Again!!) 

Check for yourself next time you're at the grocery store, Smart and Life water bottle plastic are NOT as thick as Fiji water bottle plastic, the plastic Fiji uses is DEFINITELY thicker! (I actually tried them all!!) So again, Fiji water bottles are less likely to fail. The miniscule difference in weight, between Fiji and Smart/Life) only matters to 'weight weenies.' 

As I stated in my post on "Treating Wild Water" (, in the follow-up post on Solarizing Water... 

Water bottles using P.E.T. (Poly-Ethylene Terephthalate, I've NEVER heard of anyone calling them "Pete"!!) plastic are recommended for treating wild water for two reasons: Durability and availability, water bottles using PET plastic are EVERYWHERE, it's a good product, so of course other sellers use PET plastic! My point was the SHAPE of Fiji bottles has an inherent advantage, it's less likely to roll away from you if you set it down. 

PET plastic water bottles have been used by BILLIONS of people around the world for solarizing wild water, solarizing works for two reasons: UV-A sunlight, and temperature/heat. If the temperature of the water goes above 122°F/50°C, just ONE HOUR of exposure is sufficient to obtain safe drinking water (treatment efficiency can be improved if the plastic bottles are exposed on sunlight reflecting surfaces such as a small sheet of aluminum foil or white sand/rock as long as it's NOT cool to the touch).  

Of course, ALL plastic melts at some point, but WHY would anyone put any liquid in a plastic water bottle?? Anyway, this leads to the question of chemicals in the plastic leaching out.

There are NO chemical phthalates or bisphenol A (BPA) in PET plastic, and therefore PET plastic does not leach these substances. PET plastic is approved as safe for food and beverage contact by FDA and similar regulatory agencies throughout the world, and has been for more than 30 years.

NOTE: Although BPA is not a chemical component of PET, the consensus among international regulatory agencies is that BPA is safe, and regulatory agencies in several countries and FDA have ruled favorably on the safety of BPA.


maybe bladder wasn't the right word, it's a 3 liter clear collapsible bag/plastic canteen with a blue screw on lid.  I only use it for storage at camp.

good point about the 'thinness' of the smart water bottle (and most of the others), they are too thin to use as a hot water bottle when the sleeping bag needs some help.

REI Member Since 1979