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Water Purifiers

Need help getting started? Read our four-part guide to backcountry water treatment:
Part 1: Proper Hydration
Part 2: Keeping Your Water Supply Safe
Part 3: What’s in Backcountry Water?
Part 4: Methods for Making Water Safe

Top Picks

How we choose: The best water purifiers highlighted here were selected based on 145 reviews of 28 products. Our top picks are those that are readily-available in the United States and have received the highest overall ratings from reviewers.

How we test: Trailspace is powered entirely by our community of readers. The reviews posted here reflect the real-world experiences of outdoor enthusiasts just like you.

If you've used a water purifier that you think should be listed here, please share your experience.

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Top Bottle/Inline Water Filter / Purifier

Grayl GeoPress

user rating: 5 of 5 (4 reviews)

I have been testing the Grayl GeoPress Purifier, a new, large capacity water filtration bottle, while canoeing, canoe camping, and day hiking this summer and fall. For the past three years, I have used a Grayl Ultralight Water Filter bottle, to provide clean and safe water for me and my dogs while canoeing and camping. I reviewed that bottle here on Trailspace on 10/14/18, and since then have continued to carry that bottle in my canoe bag, and occasionally, in my backpack side pockets. The new GeoPress utilizes the same fill and press filtration system as my Ultralight, but has improvements that address some of the deficiencies I found with the prior bottle. I can recommend the GeoPress for its simple operation, effective filtration performance, and increased volume. The bottle can be used by a solo paddler or hiker, but can also be used to replenish water supplies for canine or human companions.

Reasons to Buy

  • Simple operation
  • Long lasting filter
  • Durable
  • Sip top
  • Soft-press panels on lid

Reasons to Avoid

  • Tough to separate outer refill cylinder from inner cylinder
  • Requires nearly direct vertical pressure

DESCRIPTION: In the Grayl product line, the  GeoPress Purifier replaces the Grayl Quest, a similar water filtration bottle, but one which was a bit heavier, and did not have the improved features of this current GeoPress model. I am using the GeoPress as an upgrade over my Grayl Ultralight filtration bottle. The Grayl GeoPress uses a simple fill, press, and drink system to purify freshwater, but is not suitable for salt water or extremely brackish water. The filter bottle has a capacity of 24 ounces (710 ml), more than the 16-ounce capacity of the Grayl Ultralight filter bottle I have used for a few years.

Read more: Grayl GeoPress reviews (4)

MSR Guardian Purifier

user rating: 5 of 5 (5 reviews)

The MSR Guardian is a top of the line water purification system that delivers on its impressive claims. Very fast, very efficient, and largely hassle-free (requires no backflushing). Excellent for the solo hiker, but perfect for larger groups.

Reasons to Buy

  • Easy to use
  • Very fast (2-2.5L/minute)
  • No backflushing required
  • Impressive efficiency claims
  • Great for bigger groups

Reasons to Avoid

  • Initial cost may put people off
  • Getting pre-filter to engage can be annoying at times

Disclaimer: This review is purely on design, usability, durability, and my overall opinion of the product. Without access to a water testing laboratory, I cannot make any claims regarding the actual efficacy for removing harmful impurities (biological and non-biological). While I can say that I have never gotten sick drinking water filtered by the MSR Guardian, that in-itself is no validation of the claims. Without proper controls, it is merely circumstantial. Introduction: The MSR Guardian is the latest and greatest in backcountry water purification (actual wording according to MSR is "The world's most advanced backcountry purifier").  According to MSR: "Nothing is safer or easier to use for purifying the most demanding backcountry water...

Read more: MSR Guardian Purifier reviews (5)

MSR Guardian Gravity Purifier

user rating: 4.5 of 5 (1 review)

The MSR Guardian Gravity Purifier is an all-in-one water treatment system that is ideal for groups, or people needing potable water in larger volumes. Not only removing bacteria, protozoa, sediment and particulate, MSR’s new flagship purifier also removes the tiniest viruses, while also using activated charcoal to improve flavor and reduce chemicals. The Guardian’s new purge valve quickly and easily cleans the filter to maximize flow rate, removing debris.

Reasons to Buy

  • Removes most high risk microorganisms and contaminants
  • Easy to use/Intuitive design
  • Spectacular purge hose system easily cleans purifier
  • Designed well to prevent cross-contamination

Reasons to Avoid

  • Price point high, but well justified
  • Weight could be a consideration/subjective rather than a con
  • Like many other filter systems, long-term storage protocol can be daunting

Mountain Safety Research (MSR) is no stranger to water treatment, and even taking a quick look at the Guardian Gravity Purifier, it shows. MSR has been responsibly manufacturing a host of products for over fifty years. You can read more about MSR here. At the core, MSR Guardian Gravity Purifier is its hollow fiber technology. Unlike all of the other hollow fiber core water treatment products currently available, the pore size filters much smaller particles, effectively removing viruses. This technology came about via the pharmaceutical industry, where specific molecular sizes were required to be filtered for scientific testing.

Read more: MSR Guardian Gravity Purifier review (1)

SteriPEN Adventurer Opti

user rating: 4 of 5 (11 reviews)

I’m sure someone out there could prove me wrong, but the SteriPen Adventurer Opti is a foolproof tool for purifying water in the backcountry.

Reasons to Buy

  • Simple to use
  • Lightweight
  • Automatic shut off and error notification (see: foolproof)

Reasons to Avoid

  • Uncertainty of battery life
  • Odd (and costly) battery

Usage and Why I Bought It:After borrowing a friend’s SteriPen Adventurer Opti during a three-day trip, the ease of use, compact size, and effectiveness were the reasons I purchased my own. It’s been a handy little companion during many hiking and canoeing trips, making the chore of preparing water for safe consumption much less daunting (than pumping) and quicker (than tablets) than what I had been used to. Ease of Use:In only 90 seconds, a liter of water is clean to drink. That’s not too shabby, although you have to hold the pen in the water for those 90 seconds without letting go (which doesn’t sound difficult, unless you really have to pee!) Needless to say, it’s a pretty simple tool.

Read more: SteriPEN Adventurer Opti reviews (11)

Aqua Research H2gO Prime

user rating: 4.5 of 5 (2 reviews)

As an employee of Aqua Research, LLC of course I am biased towards this water purifier, but I have taken the H2gO purifier backpacking and use the disinfectant regularly. The best features in my opinion are the weight (3.8 oz) and the solar rechargability. I can stuff the purifier in the bottom of my backpack for weeks and then when I need to purify water pulled from a contaminated source I can simply hold in the sun for a couple seconds and be ready to create a disinfectant solution on the spot.

Reasons to Buy

  • Lightweight (3.8 oz)
  • Durable (10+ year life span)
  • Rapid
  • Rechrable via USB, Solar
  • Contains salt storage units within device
  • LED Flashlight
  • Unlimited doses
  • Purifies up to 10 L per dose

Reasons to Avoid

  • Does not replace filtration
  • Leaves faint chlorine taste
  • Does not remove metals from water
  • Does not permit you to drink salt water

As an avid backpacker, camper, and international traveler, I was hired by Aqua Research LLC to help market the H2gO Purifier, a small electrolytic water purifier ideal for the activities I love. Therefore, with some bias I will say that this purifier is the most unique and creative purifier on the market. I have used my PRIME model purifier for about 4 months now, and am hooked. The purifier works by converting Salt (NaCl) to Disinfectant (Sodium Hypochlorite +Hydrogen Peroxide) through an electrolytic process.

Read more: Aqua Research H2gO Prime reviews (2)

SteriPEN Ultra UV Water Purifier

user rating: 3.5 of 5 (1 review)

The SteriPen line offers a great new tech for h2o off piste. After significant time spent researching the line of products I decided on the Ultra for two reasons. One; it is rechargeable (no peculiar batteries to find) and Two; it doesn't have the battery draining "flashlight" like the Freedom.

Reasons to Buy

  • Easy to use/clean
  • Lightweight (previous filter was PUR)

Reasons to Avoid

  • H2O needs to be prefiltered
  • First use failed (subsequent uses have been flawless)

On a light and fast tour around Summit County Colorado this Memorial Day weekend I had good opportunity to goof around with the Ultra. With the low volume and minimal weight this was added to my fastpack kit with no noticeable interference to load distribution. The time saved at refills added up to over an hour. Really happy with the lack of work as compared to my old PUR (before they named the model Katadyn). More time for running. I don't even have to take my pack off to fill up anymore! As with any electronic device; learned the manual before setting off in to the wilderness. The smiley face is hilarious, but when snowflakes and lightbulbs start appearing on the screen it is helpful to know what they really mean.

Read more: SteriPEN Ultra UV Water Purifier review (1)

First Need Deluxe Water Purifier

user rating: 5 of 5 (13 reviews)

The only real choice if you want to remove all the nasty bugs/chemicals from your water source with a single self-contained device.

Reasons to Buy

  • A real chemical-free purifier
  • Removes bacteria, cysts, and viruses (to EPA standards)
  • Double pump action for faster fill rate

Reasons to Avoid

  • A bit heavier than other brands
  • Replacement filter canisters may be a bit expensive

I’ve had this First Need purifier for nearly a decade and it has served me and my hiking/backpacking buddies well. Most importantly, this is not simply a water filter but a chemical-free purifier. That means you don’t have to use the chemicals other require or the addition of iodine to make water safe to consume. This means it removes a lot of those difficult to spell pathogens that will definitely ruin your trip and possibly leave you sick/ailing long after you get back to civilization.

Read more: First Need Deluxe Water Purifier reviews (13)

Bottle/Inline Water Filter / Purifier

Grayl Ultralight

user rating: 4.5 of 5 (3 reviews)

I purchased this water filtration bottle primarily to take canoeing, for day trips and canoe camping outings. It is small, easy to carry, and can provide clean drinking water in a short period of time. It is really tough to use in the canoe, due to pressure needed, but a quick stop off at shore and I can get clean water quickly. It is also handy to use when hiking, as it fits nicely into backpack bottle pockets.

Reasons to Buy

  • Simple operation
  • Long lasting filter
  • Easy to transport/small and lightweight
  • Durable

Reasons to Avoid

  • Can be hard or uncomfortable to press
  • Limited capacity for each use

Packaging as I purchased the bottle in spring of 2018 With the unseasonably warm summer we had, and with numerous canoe camping trips on the agenda, I was looking for a simple, easy to use, and portable water filtration system/product that I could bring canoeing, camping, and hiking. Having potable water in the canoe is essential for both paddlers and dogs, and at remote canoe camping sites, relying on the lake water can be risky. Though we hike in areas with mostly clean waters, it is not wise to depend on luck when utilizing our streams for drinking water.

Read more: Grayl Ultralight reviews (3)

First Need Deluxe Water Purifier XL

user rating: 5 of 5 (4 reviews)

We have had this pump for 3 years now. Although it is a little bulky and could be a bit more ergonomically designed, it has been a lifesaver for us.

Reasons to Buy

  • Safe water supply

Reasons to Avoid

  • Bulky

This little purifier gives me peace of mind when we are camping. It is a relatively quick and efficient way to provide safe clean water for drinking. The pumping mechanism is not as ergonomic as I'd like, but it is a small price to pay for health. We use a lightweight collapsible bucket which fits inside the stuff sack with the pump to fetch water from the stream or lake. This adds another level of safety as you are not perched on a rock or steep bank trying to pump water directly from the source.

Read more: First Need Deluxe Water Purifier XL reviews (4)

More Reviews of Water Purifiers

Trailspace reviewers have shared 145 reviews of 28 different water purifiers.

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Other Types of Water Treatment

Find more water treatment reviewed in these related categories:

Pump and Gravity Water Filters

Bottle and Inline Water Filters

Chemical Water Treatments

+2 more types

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