The Katadyn BeFree is a water filter that’s ideal for anyone who wants to keep their pack weight down while out on the trail. Having regularly used it for over eight years now, I’d go so far as saying it’s the best water filter on the market. It’s been out for some time now, but this is a brand-new iteration of it, with an added activated carbon stage to improve taste, reduce odour and filter chlorine, delivering reliable, fresh-tasting water.

The Top Line

An incredibly convenient, lightweight and packable water filter that provides safe drinking water in remote places. It’s passed our tests with flying colours and is available in 500ml or 1-litre bottles.

Pros: Light and packable, excellent flow rate, effective at blocking out things like sediment and bacteria
Cons: It’s a filter and not a purifier so it won’t filter viruses. Not suited to sub zero conditions.
Filters: Bacteria, protozoa/cysts, sediment.

Buy the Katadyn BeFree 500ml AC: £42 at Wildbounds.com

How We Tested the Katadyn BeFree

I used the original version of the BeFree on some big multi-day trips, including two weeks on the Cambrian Way and three weeks running over every mountain in Wales. This latest version has been used all summer, most notably on a week-long hiking trip in Eryri National Park.

How It Works

The BeFree filters water through a mass of hollow fibres with 0.1-micron pores. These allow water to pass through but block bacteria and protozoa. There’s no pumping or UV filtration involved – just simple squeezing or sipping. It will safely filter up to 1,000 litres of water before the cartridge needs replacing (these cost around £30). The activated carbon inserts don’t last as long – each one manages up to 200 litres before you need to swap it out (around £18 for a pack of three).

How It Performs

I’ve tested a number of portable filters for backpacking and, in my experience, this one has the best flow rate. Some filters I’ve used have been agonisingly slow, whereas this one filters water almost effortlessly.
I’ve used it to filter water from mountain-top puddles in the Black Mountains, from small brooks in the Lake District and even on a trip through the wilderness of Scandinavia, and I can’t recall ever having had any stomach issues related to its use.

That said, I still exercise some caution. This filter removes bacteria, protozoa and sediment, but not viruses, which are much smaller. In most remote upland areas of the UK the viral risk is extremely low, but it can rise where there’s livestock or human activity nearby. Streams running through pasture, farmland or areas downstream of settlements can carry animal or human waste, which in turn can carry viruses. In those situations, you’d either want to boil the water after filtering, add a chemical purifier (like chlorine or iodine), or use a dedicated purifier rated for viruses as well.

Cleaning the filter is straightforward. You can hold the cartridge under running water or fill the squeezy bottle and give it a good shake. Over time the flow rate does decline steadily, but this is only after a lot of use. I’d say after about a year of regular use, from my experience.

In terms of durability, I’ve had no issues with the squeezy flask. In fact, it has always outlasted the BeFree’s filters for me. My main quibble with the previous (non-AC) version was that it came with a very flimsy bottle top that broke off easily.  I actually ended up replacing mine with the bottle cap from a Smart Water bottle. Fortunately, Katadyn has corrected this with the latest version – it’s now much more durable and better quality.

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And does the activated carbon filter work? Yes, it creates a slightly sweet taste but it does improve what would otherwise taste a bit foul, from my experience.

Just one final thing to be aware of: the filter can be damaged and its performance affected if it’s exposed to freezing conditions. If you plan to use it at high altitude or in sub-zero temperatures, keep it close to your body at all times.

Katadyn BeFree AC Verdict

For me, this has earned its place as the benchmark portable water filter and a genuinely trusted companion in the outdoors. I thought I’d dropped it on a hike the other day, but luckily it turned up at the bottom of my pack. I would’ve been gutted if I’d lost it.

I own – and have owned – all kinds of filters and purifiers, and the Katadyn BeFree is the one I turn to for any trip to the hills, whether that’s a multi-day wilderness trek or just a day hike.​ It’s a top bit of kit.

Price: £42
Weight: 76g
Buy the Katadyn BeFree 500ml AC: £42 at Wildbounds.com

Pictured below, the previous iteration being tested by our team back in 2019.