GRAYL Water Filter Bottle Review

GRAYL Water Filter Bottle Being Filled From LakeThe GRAYL is a filter bottle with an interesting twist. Where other filter bottles rely on pumps or suction, the GRAYL has worked out a novel method. You simply fill the bottle, insert the filter, and press it down. This creates pressure which moves water up through the GRAYL bottle’s advanced filter element. With a patented filter design which removes bacteria, viruses, cysts, and microscopic contaminants, the GRAYL can make water from almost any source drinkable and delicious.

As we compiled this review of the GRAYL filter bottle, we had a few weeks to put it through its paces and tested it while hiking and camping as well as messing about with it at home. Along the way we evaluated several of GRAYL’s competing bottles to put together our Best Filtered Water Bottles Guide for 2018. Ultimately, we ended up naming the GRAYL as the #1 best filtered water bottle of 2018. If you want to see some of the competition, check out that guide. If you want to learn more about the winner, keep scrolling!

Filter Testing with the GRAYL Water Filter Bottle

GRAYL Water Filter CloseupAt the heart of the GRAYL bottle’s filtration is their “patented electro-adsorptive medium.” Not only does the name have a bit of a space-age ring to it, it also works fantastically well. If you’ve looked at portable water filters before, you’ve probably come across a “Micron” rating. This generally tells you the size of the pores which the filter passes water through. While typical filters have incredibly tiny microscopic pore sizes as small as mechanical filtration, the GRAYL’s filter also utilizes electro-chemical properties like electro-adhesion and ion exchange. This allows the “electo-adsorptive medium” to capture contaminants at the sub-micron range, smaller than pretty much any other filter bottle! To put it simply: the GRAYL’s filter out-performs just about any other filter bottle on the market. It can remove the smallest contaminants, even viruses orders of magnitude smaller than many of its competitors.

After the heavy-lifting is done by the “electro-absorptive medium,” the GRAYL also passes water through a second stage of filtration. Utilizing a powdered form of activated carbon, the second stage removes certain chemical contaminants such as chlorine, heavy metals, and trace pharmaceuticals, while also improving the taste and odor of the water. Finally, the filter element contains silver zeolites, a natural anti-microbial. This helps prevent bacteria growth inside the filter element, keeping it clean and free from nasty buildup.

Berkey Water Filters

Using the GRAYL Filter Bottle

GRAYL Water Filter BottleUsing the GRAYL filter bottle is intuitive and even fun. The bottle consists of three pieces: the “outer refill” sleeve, and the “inner press” bottle, to which the third piece, the purifier cartridge, attaches (pictured right.) To filter water, you fill up the outer refill sleeve with water, then press the inner press with the purifier cartridge at the bottom down into the outer refill sleeve.

You definitely feel a bit of resistance as you force the press down into the water. This is why GRAYL recommends setting the bottle on a relatively flat surface and pressing down to get some mechanical advantage, keeping the arms straight. The resistance you feel is why the design works so well. The pressure required really helps drive the water through the filter, giving you a highly effective filtration. The GRAYL manual says it takes about 15 seconds of pressing down to get your water filtered. For the GRAYL bottles 16 ounce capacity, that’s just over one second per ounce. A flow-rate of around 2 liters/minute.

After a bit of use, we’ve come to quite enjoy filtering water through the GRAYL bottle. It gives you a little bit of a workout for your water, which is always good, but it is not tedious and 15 seconds is just long enough to keep it fun.


Versatile Filter Bottle Design

Woman filtering water through her GRAYL bottle while hikingThe GRAYL bottle offers a much more flexible filtration solution than many other filter bottles. Because you don’t need to rely on suction to pull water through a straw like the vast majority of bottles, you can easily share water filtered from your GRAYL. Although the GRAYL bottle itself has a relatively small capacity at 16 ounces, you can easily filter multiple bottles worth of water and pour them into a larger water bottle. This allows you to filter water not only for yourself, but also to share with others, cook food, or even for personal hygiene use.

Since it takes around 15 seconds to filter 16 ounces of water, this is not exactly something you’ll be filtering gallons and gallons of water with. However, in the context of a filter bottle you use while camping, hiking, or as part of your emergency kit, the GRAYL goes a long way. The filter has a lifetime of about 40 gallons, or 300 uses of the 16-ounce bottle. After that, the USA-Made filter replacement cartridges cost around $25.

Durability & Field Testing

GRAYL Fill Press Drink Photo MontageAccording to all of its advertising, the GRAYL has been built from the ground up as a bottle ready to face the elements. Overall, we feel they have done a good job of accomplishing this. The bottle is made from a BPA-free “ultralight” plastic. It is very durable, and as the name would imply, ultra-light. Empty, the GRAYL bottle with filter weighs just 10.9oz. With such a low weight and a small footprint, the GRAYL easily disappears among your gear. Even full, at 26.9oz, it remains remarkably light.

Aside from a few scuffs and dings, our GRAYL filter bottles show no serious damage or any wear that impacts their functionality. We’ve taken them on several multi-day camping outings and used them quite liberally. They have held up very well structurally. Filter quality is truly exceptional, turning even the most questionable stagnant puddles into something you might even enjoy drinking.

One thing to note is that due to the GRAYL’s outer sleeve/inner bottle design, you have to be a bit careful to make sure you’ve got a good seal. Otherwise you can end up with some leakage, but this has not been a major problem for us. However, without attending to it rather carefully when securing the bottle, you could end up with a mess.


More Filter Specifics

GRAYL Water Purifier Bottle Replacement FiltersEvery filter in the GRAYL purifier bottles is made in the United States, based on GRAYL’s patented design. Tested to meet NSF/ANSI standards 42+53, the filters have been evaluated by independent labs as well as tested in the real world by thousands of GRAYL’s customers. The filters are capable of removing viruses like Rotavirus, Hepatitis A, and Norovirus, as well as bacteria like Salmonella, E. Coli, and cholera, and protozan cysts such as Giardia, among many others too numerous to list here.

In addition, the GRAYL’s activated powdered carbon filter can remove heavy metals like arsenic and lead, as well as eliminating the taste and odor of chlorine. Other chemicals such as benzene and traces of pharmaceuticals are also trapped in the carbon filter.

Review Summary

GRAYL Water Filter Purifier BottleWe’ve quite enjoyed our time testing our GRAYL filter bottles. We give them top marks for the unbeatable filtration quality combined with a unique and highly functional design. For some, the GRAYL’s ~$60 price-tag might be a turn-off, but there are few filters on the market which can boast the quality of filtration of a GRAYL bottle. The price is also backed up not only with the truly exceptional filters, but also a sleek, well-designed, durable, and supremely lightweight bottle.

Our main issues with the GRAYL bottle concern its rather small capacity at just 16 ounces. While this goes a long way towards making it fit easily into your gear or emergency kit, we would prefer an Extra Large version for those who want to filter more water at once. As it stands, we feel the GRAYL bottle is best used in concert with a larger water bottle or container to store filtered water beyond the GRAYL’s 16 ounce capacity.


The second issue has to be its filter lifetime. At 40 gallons, or 300 uses, it is definitely a bit on the small side. This is compounded by the relatively high cost of replacement filters at around $25. For the casual user this is more than enough to get you through years worth of camping or hiking trips. But for those with a more competitive appraisal, we have to note that there are certainly more affordable filter bottles, both in terms of initial investment and replacement filter cost.

On the whole, filtering water through the GRAYL is a lot of fun. It’s also highly effective. The design works smoothly, offers a novel experience, and lets you engage with the process of purifying your water. If you are looking for the top-of-the-line water filter bottle, look no further than the GRAYL. We award it 5/5 stars, as well as the title of Best Filtered Water Bottle 2018.

Learn More About the GRAYL Water Filter Bottle

Learn more details, check current prices, read other customer’s reviews, and much more at the GRAYL Water Filter Bottle Amazon Listing.

Didn’t find what you’re looking for? Head over to our Best Filtered Water Bottles Guide 2018 or our Filtered Water Bottle Buyer’s Guide for some more suggestions!


One of the best filters on the market – removes bacteria, viruses, and common contaminants
Lets you filter from practically any source
Fun to use


Small capacity
High cost of entry
High cost of replacement filter

  • Editor Rating
  • Rated 5 stars
  • 100%

An innovative water filter bottle equipped with an incredibly high-tech filter capable of trapping the tiniest contaminants.

1 thought on “GRAYL Water Filter Bottle Review”

  1. Have you tested this over a long period of time, like a week of filter all your water? I did not have great outcomes with extended use.


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