Expert Review: Grayl Ultralight Water Purifier Bottle

Published on 08/26/2022 · 7 min readThis review is my honest opinion of the water purifier, which I purchased with my own money in August of 2019.
Hunter Reed, Camping Expert
By Camping Expert Hunter Reed

All photos courtesy of Hunter Reed

About this Review: This review is my honest opinion of the water purifier, which I purchased with my own money in August of 2019.

My take

The Grayl Ultralight compact purifier bottle is the easiest, most practical water filtration device I have ever come across. I have used it everywhere from the remote wilderness in Utah to hotel sinks in Mexico, and even once at a boat rinse-off station in Hawaii; it has never let me down. It is ideal for backpackers, day hikers, and those traveling to new cities.

Filling up the outer bottle with stream water

About the purifier I own

  • Model: Grayl Ultralight Compact Water Purifier
  • Size: 16oz

About me

  • Experience: 20+ years of backpacking

Test conditions

  • When I bought it: August 2019
  • Days tested: 300+
  • Where I’ve used it: All over the wilderness in Colorado, Utah, Oregon. Non wilderness areas in Hawaii and Mexico
  • Seasons I’ve used it in: Fall, spring, summer, winter
  • Used for: Only water

How it performs

Ease of Use

What I was looking for

When I purchased this water purifier bottle, I was headed out on a three-day backpacking trip and needed a way to filter water. I hate the taste of iodine tablets or aqua mura; I often find that if I use these methods, I don’t drink as much water as I should because it’s so hard to get it down. I wanted a hassle-free way of filtering water that wouldn’t taste terrible.

Backpacking in Summit County, CO with my Grayl in the side of my pack!

Why I chose this gear

I bought this product because it doubles as a water bottle and it seemed really easy to use. Most water filtration devices require some sort of pumping mechanism or a tablet that dissolves in the water. This simply requires removing the internal part of the bottle, filling up the external part, and pushing the internal part back in. As it’s pushed back in it filters the water.

The outer bottle and the inner bottle with the filter on the bottom (orange)

What I love about it

  • Durability: I wasn’t sure what to expect in terms of its durability. This is only because this bottle is plastic and I had never heard of Grayl before purchasing. But this bottle has lasted a long time and still has a ton more life in it. I have replaced the filter once ($25 and really easy to screw on and off), but there is no damage to the bottle. The base has silicone on it, so even if I were to drop it, I don’t think it would break. There is also a 10-year warranty on every Grayl bottle.
  • Packability: The Grayl Ultralight compact purifier bottle is super packable. It is a small size, weighs around 10oz while empty, and slips into a water-bottle pocket on any backpack. Given that it is also a water bottle, I find it more practical to pack this compared to a pump water-filtration setup.
  • Ease of use: This water purification bottle is so easy to use. There are two separate bottles nestled inside each other. The outer one is just a shell, and the inner one has a filter on the bottom. I fill the shell up with water from the source and push the inner bottle down into the outer shell. As I push down, the filter on the bottom of the inner shell filters the water that I have put in the outer shell. Afterwards, the water in the inner shell is filtered and I can drink from it like a regular bottle. It is also super easy to change the filter when the time comes (check Grayl website on info for when to change the filter).
  • Backpacking: I always bring this water bottle backpacking. It is really useful given its dual purpose. It is easy to carry it in the water-bottle holder on the side of my pack so that I don’t need to dig around for my water filter if I come across some water on the trail.
  • Car Camping: When I car camp, I have a large container of water with me that I keep in the car, but this is a great backup to keep in the truck in case I need it.
  • Versatility: I will bring it with me on every international trip to minimize my plastic water bottle usage; and I bring it on every camping or backpacking trip as a means of water purification. In the case that I don’t need to use the filter, it doubles as my water bottle to bring around when doing activities or sight seeing. It has always kept me safe and healthy in any situation.

Issues I’ve encountered

  • Leakage: Though it hasn’t happened too much, I have had a few times where water would leak out of this bottle when it’s tipped on its side. The filtered water seems pretty secure, but the small amount of water left between the outer and the inner sections of the bottle sometimes escapes. It isn’t a huge issue in terms of losing my water, but it has gotten my pack wet.
  • Size: One of the selling points of this bottle is that it is so packable. However, I find that its 16oz capacity is not enough to last me very long in areas without many water sources. I will always bring another water bottle along on backpacking trips. But even if I am doing a day hike, I run out of water pretty fast if this is the only bottle I use.
  • Temperature Retention: Though the Grayl does better than a Nalgene bottle, it isn’t great at temperature retention. I have never had any issues with freezing, but I have had my water get warm fast when hiking in warm areas.

To filter the water you just push the inner section down into the outer bottle which is filled with water, and the inner bottle ends up being filled with filtered water!

Favorite moment with this gear

This one is kind of silly, but my favorite moment with this water bottle was when I was on a trip to Hawaii. I was visiting a friend, and we had gone paddle boarding at a bay a few hours from where we were staying. We had drunk all of our water by the time we got back to shore. There were no businesses nearby, but there was a ton of traffic to get back to town. I can't think of many other times I have been this thirsty. The only thing around us was the ocean and a fresh-water boat rinse off. It was really our only option—it would be at least an hour before we made it back somewhere with water. We went over to the boat rinse off and used one of the two hoses to fill up my water bottle and filter the water. I tried it and it tasted totally fine. There was a group using the other hose who looked at us like we were crazy, but we were so happy to have found water. And we never got sick. The next time I went back to visit my friend, I found she had bought the same bottle because she was so impressed.

Value for the money vs. other options

I’m confident this bottle is worth $70. In fact, I think that’s a screamin’ deal given the versatility and compared to other purification options. It comes with a filter, and replacement filters are $25; each filter is good for 300ish uses (more info about this can be found on Grayl’s website). This ends up accounting for around 37 gallons per filter. Water treatment tablets are around $20 for 30 gallons, taste terrible, and do not double as water containers. Any other pump type filter will be around $70 and will only be an extra piece to carry in a pack. I think this is, hands down, the best purification method on the market.

Final verdict

The Grayl Ultralight Compact Purifier bottle is the most practical, easy way to ensure I have access to clean drinking water no matter where I am. I truly think everyone should own one of these, regardless of whether or not they are a backpacker or simply like traveling to new cities.

Out of stock
Hunter Reed, Camping Expert
Hunter Reed
Camping Expert
10 Reviews
99 Customers helped
Share article:

Curated experts can help

Have a question about the article you just read or want personal recommendations? Connect with a Curated expert and get free recommendations for whatever you’re looking for!

Shop Camping & Hiking on Curated

Big Agnes Rapide SL Insulated Sleeping Pad
Nemo Aurora Tent w/ Footprint

Browse more GRAYL Camping & Hiking

Mystery Ranch Terraframe 3-Zip 50L Pack · Men's
Nemo Forte 20 Sleeping Bag · Men's
Osprey Talon 22 Backpack- Men's
Osprey Tempest 20 Backpack
Garmin Epix (Gen 2) Smartwatch
Nemo Aurora 3 Person w/ Footprint Tent · Olive Green

Browse more GRAYL Camping & Hiking

Written by:
Hunter Reed, Camping Expert
Hunter Reed
Camping Expert
10 Reviews
99 Customers helped

Read next

New and Noteworthy