t’s hot, you’ve been on the trail for hours and you sucked your water bladder dry long ago. But look over there! The water in that stream sure looks delicious and you swear it’s flowing and didn’t you read once that moving water is safe to drink?

Well I hope you’re nearly home, my friend, because best case, you’ll be spending the next day in the bathroom.

That is, unless you have our top pick for water purification, the Grayl Geopress.

Why Do I Need One?

For this review, we looked at water purifiers for use doing fun stuff, like:

  • Hiking
  • Backpacking
  • Camping
  • Mountain biking
  • Adventure motorcycle riding
  • UTVing
  • Overlanding
  • Traveling internationally

Of course, anything that’s useful for activities like these is also useful to have around for emergencies, which, as we saw during the Great Toilet Paper Shortage of 2020, doesn’t have to involve zombies. It’s just smart to plan for tough times.

What we’re NOT concerned about here is purifying your home or office water (just get a reverse-osmosis system) or hydrating a large group of people (order a Katadyn Expedition Filter).

You do NOT want to meet this guy in a dark alley. Trust us. Cryptosporidium photo courtesy Wikimedia.

Jobs to Be Done

It doesn't matter if we're talking mountain bike tires or sailing schools, one size never fits all. Each of us has different goals, skills, funds, etc. so when Adventure Monkey conducts its reviews, we always first ask, what is the job I want this thing/service/person to do for me? Why would I hire it vs. all its competitors (or even why hire any of them)? Then we rate against those criteria.

(Jobs to Be Done theory comes from the business world, used to ferret out why customers are really buying your product or service. We find it a perfect framework to use from the other direction, helping us decide where to spend our money. Explanation here.)

For Adventure Monkey activities, a water purifier must:

  • Let me drink from a stream, pond or puddle without worrying about it. At. All. (Sure, we don’t usually have to worry about waterborne viruses in the U.S., but ideally we don’t even want to think about it.)
  • Get good, safe water in our bellies as quickly as possible. We don’t want to wait four hours to ensure all the Cryptosporidium is dead. Actually we don’t even want to know what that is.
  • Ideally improve the taste. Unless we’re as dry as a Mummy sandstorm, it’s much nicer to not taste the chlorine or iodine from a disinfecting tablet.
  • Be portable enough to toss in a backpack or motorcycle bag.
  • Not be a princess device, requiring constant maintenance.

You can channel Grizzly Adams and boil water, or pretend you’re George Jetson and use UV rays, but the goal is the same: kill all the critters in the water that want to hurt you. What may or may not be in the water determines what you want to use and how long it takes.

And what’s the result if we don’t kill these guys? As the CDC notes, for protozoa like giardia and cryptosporidium expect good times with, at best, gastrointestinal illness (for example, diarrhea, vomiting, cramps).

Hard pass. And if there’s a chance that viruses are swimming in that water, you’re now opening yourself up to hepatitis, meningitis and other nightmares.


There are a thousand solutions for purifying your drinking water, but the main categories for portable options are:

  • Boiling. No special tools needed, just a heat source that will let you get the water to a rolling boil for at least 1-3 minutes.
  • Filtration. The type of filter media and size of the pores determines how broadly it works. Example: to filter out waterborne viruses, the pores must be no larger than 0.02 microns.
  • Chemical. A confusing number of options here in both liquid and tablet form: iodine, chlorine, chlorine dioxide, bleach and more.
  • UV light. Literally sterilizes using ultraviolet light. Magic.

The Best Water Purifier

Just get it and stop worrying about water

Grayl's Geopress gets our vote as the water purifier we always want with us, whether we're riding the backroads of Utah or hiking in Peru. Heck, we even keep one in the get-home bag in each of our vehicles.

Why? First of all, it perfectly solves each of the jobs we defined above. But there are even more reasons:

  • It filters EVERYTHING, including viruses.
  • It's actually a water bottle, so it's super convenient. Other filter solutions require pumps, tubes, bags and other junk that just gets damaged and misplaced.
  • It's stupid-easy to use.
  • No batteries to worry about (looking at you, UV lights).
  • Very little that can break, leak, tear, whatever. It feels solid in the hand. Grayl should have a bear play with it, like Yeti.
  • No chemical taste and you don't have to memorize dosages (e.g., how many drops or tablets per liter of water).
  • Replacement cartridges are small and have a 10-year shelf life, perfect for all you preppers. Each cartridge is good for about 65 gallons.
  • It's really not that expensive! 90 bucks + 30 bucks for each additional cartridge. Go compare it to other filter solutions that will handle viruses.

How to Use It

We really cannot express how easy it is to use this thing. Seriously, it sounds Too Good To Be True™️.

  1. Fill the outer container
  2. Crack open the twist top
  3. Push down on the inner container

That's it! You can purify water without even putting down your beer.

Fill the outer container and push down on the inner. End of instruction manual.


We also have Steripens, LifeStraws, water purification tablets and other solutions that we use and carry for backup, depending on our needs and expected water sources. But for an all-around purifier that we don't have to think about, regardless of where we are in the world and what we're up to, the Grayl Geopress gets the Adventure Monkey seal of approval and makes our Essentials list.

Adventure Monkey's Best Water Purifier.


Jan 22, 2021

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