Grayl
Grayl UltraPress Purifier Bottle
- Protection: 10/10 What it removes from water, and how well that is proved.
- Flow rate: 10/10 How fast clean water comes through when it is new. Real flow drops as it clogs: see Ease of use.
- Weight: 4/10 How much it adds to your pack.
- Ease of use: 8/10 Filling, squeezing or pumping effort, how fast it clogs in peaty or silty water, and how easy it is to clean.
No shop we checked has it in stock
Travel where tap water is doubtful: it also removes viruses
- Type
- Bottle
- Removes viruses
- Yes
- Flow
- 3 L/min
- Weight
- 354 g
- Rated life
- 150 L
Where to buy
Wild Bounds £89.95 Out of stock. Forest Blue and Black Camo. Free UK delivery over £50.
View at shop: Wild BoundsPrices checked 8 Nov 2026 on each shop's own page; shops can change them. We earn no commission on these links; shops are listed by price. More
Our ratings (out of 10)
1 to 10, compared with the whole market. Each says what it's based on. How we score
Protection
From maker's figures 10/10What it removes from water, and how well that is proved. 10: The best you can buy for this.
Bacteria, protozoa and viruses (99.99% of viruses, 99.9999% of bacteria, 99.9% of protozoan cysts) to the US EPA Guide Standard and Protocol for microbiological purifiers, tested by an independent lab (Grayl). A named standard for all three, so 5. Grayl says it holds no NSF or WQA certification.
Flow rate
From maker's figures 10/10How fast clean water comes through when it is new. Real flow drops as it clogs: see Ease of use. 10: The best you can buy for this.
Grayl gives 10 seconds for 500 ml, about 3 L/min, new cartridge, clean water. 2.5 L/min or more. Too Many Adapters timed a little over 10 seconds a bottle with a new filter. Off the Atlas found the press slow in near-freezing water. Grayl says to replace the cartridge when a bottle takes 25 seconds.
Weight
From maker's figures 4/10How much it adds to your pack. 4: A bit below average.
354 g empty (Grayl). 300 to 449 g. It is also the bottle you drink from, so you carry no other.
Ease of use
From reviews 8/10Filling, squeezing or pumping effort, how fast it clogs in peaty or silty water, and how easy it is to clean. 8: Clearly better than most.
Fill, press and drink in about 10 to 15 seconds. Too Many Adapters (4) found it easier to press than the older Ultralight and simple to use. SectionHiker (4) was impressed by its ease of use. Treeline (4) found the press easy with minimal effort and the filling intuitive. Off the Atlas (4) found it easy and practical day after day but slow to press in near-freezing water. Average 4 out of 5, so 8 out of 10. SectionHiker had a free bottle from Grayl, which it says.
In short
Good for
- Travel where tap water is doubtful: it also removes viruses
- Day walks and short trips with water sources close together
- A bottle that fits a rucksack side pocket or a cup holder
Strengths
- Removes viruses as well as bacteria and protozoa, to the US EPA protocol (Grayl)
- 500 ml of purified water in about 10 seconds, no pumping
- Rotating handle gives a flat pressing surface and easy carry
- One-way valve lets you add electrolytes or drink mix to the clean side
- Grayl says it can be used in freezing temperatures, with no more than 2 freeze and thaw cycles on a cartridge
Weaknesses
- 354 g empty: heavy for a filter, and holds only 500 ml
- Cartridge lasts only 150 L and slows fast in silty water
- The spout cap is not tethered and is easy to lose (Off the Atlas, Treeline)
- Grayl holds no NSF or WQA certification
- Grayl says to avoid using a cartridge after 3 or more freeze and thaw cycles
Sources
We haven't tested this ourselves. Every score comes from these specs, tests and reviews.
ShowHide sources (6)
- Grayl: UltraPress Purifier, specs
- Grayl: FAQs (freezing, no NSF or WQA certification)
- SectionHiker (Philip Werner): Grayl UltraPress water purifier bottle review (free bottle, disclosed)
- Too Many Adapters: Our GRAYL UltraPress review
- Treeline Review (Karthika Gupta): Grayl UltraPress water purifier review
- Off the Atlas: Grayl UltraPress review, two Pakistan expeditions