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3 Portable Water Purifier Bottles Perfect for Travel and Outdoor Adventure

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Whether hiking, backpacking or traveling, water filtration and purification is important. But not all portable water filters do both. So we’re gonna compare three portable water purifiers and filters in one and explain why it’s important to do both (and simultaneously avoid dysentery and giardia…)

Because you see, natural water sources like those found in the outdoors are very often swimming with giardia, rotavirus, hepatitis A, dysentery and more nasties that can make you super duper sick. And they can be found in just about any body of water: rivers, lakes, streams, ponds… And just because a stream “looks clean” doesn’t mean it’s not full of viruses, bacteria, and protozoa.

So if you’re on a backpacking trip or day hike or are mountain biking through the woods and need to fill up the ol’ water bottle, no matter where you’re filling it, you need to filter (and purify).

So maybe you already knew that and you went out and got yourself a handy dandy portable water filter like a Sawyer or a Lifestraw (or another filter you saw us mention in our post about backpacking water filters). Awesome. Good call. But here’s the thing: filtration is not the same thing as purification.

Portable Water Purifier Bottles: filling a water bottle from a stream
Filling a GRAYL water bottle from a stream

Filters like the Sawyer Mini and the Lifestraw Universal are excellent at filtering out particulates like dirt, heavy metals and chemicals plus protozoa like the dreaded cryptosporidium cyst as well as bacteria, but they don’t capture viruses, which are too small and pass right through most filters. That’s where purification tablets like Aquatabs or Iodine drops come in, which work in conjunction with filters as a “double tap,” if you will, Because tablets kill viruses and bacteria, but can’t touch protozoa like giardia.


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The only way to kill all the baddies: boil your water or use a UV wand like a Steripen, ‘cause those two methods will kill everything!

OR, double up and utilize a filter AND a purifier tablet on all the water you collect and drink (or cook with) in the outdoors. If you wanna be extra safe about it, anyway.

At least, that’s what’s always had to be done. But these three brands are making portable water purifiers and filters in one in order to simplify the whole backcountry hydration process and make all your drinking water safer.

So we tested them out on a few recent outdoorsy excursions to see how they performed (and whether we got sick…we didn’t). Here’s a breakdown of 3 portable water purifier and filter bottles to help you figure out which one is right for you.

Portable Water Purifiers and Filters in One

GRAYL Portable Water Purifier Bottle
GRAYL Water Purifier Bottle

GRAYL Purifier Bottle

The GRAYL portable water purifier bottle comes in two sizes: the GEOPRESS, which purifies 24 oz, and the Ultralight Compact, which purifies 16 oz. It filters out 99.9% of viruses, bacteria and protozoa with a single press (no squeezing or waiting required). But it also filters out microplastics, chemicals and heavy metals, making water from dubious sources taste better, all thanks to activated carbon and an ion exchange in the filter.


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The orange purifier cartridge is good for 350 presses (300 for the ultralight) and is completely replaceable. As for winter usage, the filter itself can withstand up to two freeze-thaw cycles, but as with most filters, you want to avoid freezing if at all possible to prolong its life.

How it works

Scoop or pour water that needs to be purified into the outer vessel. Make sure not to overfill past the fill line. Then place the inner bottle on top and press down. It takes a few seconds, and you have to make sure the cap is slightly open to vent air as you press, but then all that’s left to do is chug or pour into your kettle or hydration bladder.

  • Pros:
    • Excellent multi-functional bottle: It works for drinking, but also refilling hydration bladders or filtering and purifying water for rehydrating or cooking.
    • Keeps dirty water separate from clean drinking water, easily preventing cross-contamination
    • Improves taste
  • Cons:
    • Takes a bit of effort to press
    • Heavy if you’re counting ounces (The GEOPRESS is 15.9 oz and the Ultralight is 10.9)

Who it’s for

For those who don’t mind a little extra weight for a truly multi-functional filter that allows you to chug water, refill other bottles or bladders, even use for cooking, the GRAYL is an excellent portable water filter that also purifies water from dubious sources. Use it for hiking, backpacking and travel. It’s also great for those who don’t already have a cabinet full of water bottles and want a durable, well-designed model.

Find the GRAYL Purifier Bottles here ($89.95, $69.95) and the replacement filters here.

RapidPure Universal Purifier bottle adapter Portable Water Purifier Bottle
RapidPure Universal Purifier Bottle Adapter

RapidPure Universal Purifier Bottle Adapter

The RapidPure Universal Purifier Bottle Adapter is also available with a RapidPure bottle if you prefer, and is a filter/straw/lid combo that fits on just about any wide-mouth water bottle (Nalgene, Camelbak, Kleen Kanteen, or HydroFlask). The RapidPure line also includes a gravity filter and all the brand’s portable water filters also purify. 

The brand uses their proprietary UltraCeram technology in the replaceable filter that removes 99.9% of viruses, bacteria and parasites, including cysts. It comes with two stars lengths to accommodate different size bottles and the filter can survive one freeze-thaw cycle and still purify water and multiple freezes and still function as a filter. The filter works for 200 gallons while the purification feature is rated for 25.

How it Works

It’s easy: all you have to do is pop on the lid with the attached filter and straw and sip away. No pressing, waiting, or squeezing and little to no risk of cross-contamination (just don’t drink straight out of the water bottle until you’ve washed it).

  • Pros:
    • Super fast flow rate makes sipping quick and easy
    • No risk of cross-contamination
    • Improves taste
    • Easy to use
    • Can use with your favorite water bottle
  • Cons:
    • Only purifies up to 25 gallons (but filters 200)
    • Only usable for drinking straight from a water bottle with attached straw

Who it’s for

The RapidPure Universal Bottle Adapter is perfect for anyone who just needs to filter and purify water for sipping, not cooking or filling up hydration bladders. That makes it a solid choice for day hikes or outdoor excursions that only last a few hours or so, or for anyone who just doesn’t use a bladder and usually boils water for cooking. Its fast flow rate makes it great for sucking in a lot of water with every sip. But since the purification aspect is only rated for 25 gallons, it’s best for those who are more concerned about filtration that purification or who don’t mind using purification tablets in conjunction with a filter bottle.

Find the RapidPure Universal Purifier Bottle Adapter here ($44.95) and replacement filters here.

Epic Water Filters Portable Water Purifier Bottle
The Outdoor Answer from Epic Water Filters

Epic Water Filters The Outdoor Answer

This portable water purifier is another filter with straw and lid combo that is also available with a bottle if you need one. Choose The Outdoor Bottle, which turns your favorite bottle (Nalgene, Camelbak, Hydroflask and more) into a purification bottle. You do have to specify which bottle you want to use it with when ordering, but it comes with two lid options: a sport cap with a protective cover and an easy-flip cap, plus two straw lengths to accommodate different bottle sizes. The filter works to remove 99.9% of bacteria, viruses and cysts, plus heavy metals and chemicals and it works for up to 100 gallons.

There’s also a separate The Answer filter available from Epic that is designed to filter tap water and is more suitable for international travel if that’s more your style. Also, fun fact: Epic filters are recyclable and the brand’s packaging is 100% compostable. If you can’t easily recycle the #7 plastic where you live, save up at least 4 used filters, mail them back to Epic and they’ll thank you with a free replacement filter.

  • Pros:
    • Two lid options (one of which is nice and sturdy)
    • No risk of cross-contamination
    • Improves taste
    • Easy to use
    • Recyclable filters
    • Can use with your favorite water bottle
  • Cons:
    • Slower flow rate than other straw filters
    • Only usable for drinking straight from a water bottle with attached straw

Who it’s for

The Epic Water Filters Outdoor Answer is perfect for anyone who just needs to filter and purify water for sipping, not cooking or filling up hydration bladders. That makes it a solid choice for day hikes or outdoor excursions that only last a few hours or so, or for anyone who just doesn’t use a bladder and usually boils water for cooking. The flow rate isn’t quite as impressive as the RapidPure, but the extended purification capabilities more than make up for it. We love the brand’s emphasis on sustainability and recycling, and appreciate the option to use our own water bottle to reduce waste.

Find the Outdoor Answer here ($34.95) and the replacement filters here.

Epic Water Filters Portable Water Purifier Bottle
The Outdoor Answer with one of our trusty Nalgenes

Bottom Line

These portable water purifier bottles are an amazing thing to have whether you’re hiking, climbing, backpacking, traveling, you name it. Wherever your adventures take you, they ensure the water you sip from natural sources (or from taps in less developed countries) is safe to drink (and won’t give you dysentery). So which one would fit best in your pack? Let us know in the comments. And if you have a question we didn’t address about water bottles or purification or filtration, ask away! If we don’t know, we’ll find out.

Drink clean water, don’t get giardia, and wander on.

*This post contains affiliate links. That means if you buy a water filter after clicking on said links, we may receive a small percentage of the sale, which means we might be able to filter and purify water on our own adventures. Thanks for keeping yourself (and us) from getting e.coli…