Best Lightweight Water Filter

1. Katadyn Befree Water Filter

Price: £32
Weight: 67g
What we like: light, excellent flow rate
What don’t like: the bottle is a little hard to clean

The design of the Katadyn BeFree Water Filtration System is deceptively simple. It consists of a sports bottle-type top that screws onto a squeezy Hydrapack plastic pouch. Hidden in the top, however, is a hollow fibre filter and EZ-clean membrane with 0.1 micron-wide holes that block out nasty bacteria and protozoa but allow clean water to pass straight through.

We this on a five-day hike along the Snowdonia Slate Trail and were impressed by its effectiveness. We particularly like the good flow rate, which means there’s no need to suck the water through the filter. This allows you to easily decant clean water into another cup or pot.

The capacity of the pouch is 600ml, while the BeFree will filter up to 1,000 litres of water. That’s not quite as long a lifetime as some other filters, but still offers pretty good value given the relatively low price. All in all, it’s a lightweight, affordable and effective portable water filter that works well and has a good flow-rate. That’s why it takes our best buy pick.

Read our full Katadyn Free review.

Best Gravity Filter for Groups

2. MSR Autoflow XL Gravity Filter

Price: £85
Weight: 340g
What we like: high volume, versatile
What don’t like: requires regular maintenance

As you can probably guess from its whopping 10-litre capacity, the AutoFlow XL filter from MSR isn’t strictly a personal water filter. This one is primarily intended for group and basecamp use. You simply fill it from a stream or river and hang the bag from, say, a branch or fence post. The gravity-fed filter will then do its thing at the rate of 1.75 litres per minute.

OM Editor Will Renwick was certainly impressed. “In terms of durability and reliability, I haven’t had any problems; it seems tough and the rolltop is certainly watertight”, he said. “I also like the fact you can quickly disconnect the hose when you need to venture with the bag to find water. This thing works, and works well.”

Though it’s almost certainly overkill for personal use, the Autoflow XL is a great system for anyone planning a backpacking trip with a group.

Read our full MSR Autoflow XL Gravity Filter review

Best Portable Water Purifier

3. Lifesaver Wayfarer

Price: £95
Weight: 323g
What we like: compact, good value
What don’t like: lots of components, carbon discs don’t last long

Lifesaver has brought out some very good water purifiers over the years. This one is the best so far. By no coincidence, it’s also their lightest. In fact, it’s one of the lightest purifiers around – aside from tablets of course. And it’s about the size of an, um, guinea pig, so it’s easy to fit into a backpack. We found it conveniently fits into the side mesh of most packs. 

To operate it, you drop its scavenger hose into a water source, give it’s little handle a few bumps and water will start moving through the body of the purifier and then out of its smaller straw, which you can place into whatever you want, be that a cup, bottle or straight into your mouth. 

It uses a two-stage filtration process to remove everything from bacteria, viruses, protozoa and cysts and that’s from up to 5000 litres of water. When you’ve maxed out that litreage (you’ll know because you pumping will get really hard), you’ll need to replace the filter, with spares available on the brand’s website. 

There’s also an activated carbon disc that reduces chemicals and improves taste and odour. This, unfortunately, will stop doing its job after 100 litres and, if you want to replace it, you’ll need to buy another one from Lifesaver for a not-so-cheap £20.99 (that’s for a pack of three).

Best Water Filter Bottle for Hiking

4. Lifestraw Go Water Purifier

Price: £38
Weight: 168g
What we like: durability, good for every-day use
What don’t like: quite heavy, flow rate slows over time

The LifeStraw Go combines Lifestraw’s patented two-stage straw filter system with a standard 650ml plastic water bottle. The 0.1-micron filtration is able to remove 99.999 per cent of bacteria and protozoa from water sources, though not viruses. That should still guarantee safe drinking water in most outdoor scenarios though.

The Lifestraw Go is very easy to use. You just fill up the bottle, screw the lid shut and suck water out through the filter. It’s a different method to the squeeze filters from Katadyn and Sawyer or Lifesaver’s plunger-type mechanism. Though effective, it does mean the Go is only suitable for personal use, since you can’t decant or siphon water into other bottles or cooking pans, for instance.

Read our  full Lifestraw Go Water Purifier review

Best of the Rest

5. Lifestraw Peak Solo

Price: €33
Weight: 48g
What we like: very light and compact, good versatility
What don’t like: flow rate slows with use

This is essentially a new and updated version of the original Lifestraw. They’ve taken the same tech but packed it into a smaller, lighter and sleeker design – and we’re into it. We’ve been confident using this in the UK’s mountains and protecting us from bacteria, parasites and just nasty bits and bobs in the water. 

This is a really handy filter that you can use as a straw to drink straight from a water source – or, if you want to keep your knees clean, from water scooped into a cup. You can also screw it onto any bottles with a standard mouth and that includes Coca Cola bottles, Evian bottles or your own re-usable – anything with a 28mm threaded top. 

With hard bottles, you’ll need to suck to get filtered water out which isn’t ideal for filtering water for a group. The simple solution there, however, is to use a soft bottle that means you can squeeze water out into your group’s containers. 

At brand new it’s capable of filling a 1 litre bottle in just 20 seconds. Bear in mind that, from our experience, that speed does decline over time, especially if you’re using the filter with really mucky water. You can clear it out using the custom backwash syringe that it comes with though and that does help to maintain the flow rate. If you take care to not leave this with water in it through freezing conditions and if you avoid sucking in too much detritus, this should provide up to 2000 litres of filtered water. The final thing worth knowing is that for every one of these that’s sold, a child will receive safe drinking water for a year. 

6. Platypus QuickDraw Water Filter System

Price: £30-40
Weight: 68-100g
What we like: lightweight, good value, good flow rate
What don’t like: short cartridge life

The Platypus QuickDraw removes any worries about water contaminated by dirt, bacteria or protozoa and brings a quick flow rate of up to 3L per minute. It’s also very packable, with the QuickStraw filter rolling up neatly within the reservoir when the filtration isn’t required.

The filter can be used separately from the reservoir if you simply want to suck water directly from a source, or you can even attach it to a standard plastic bottle if needs be. The reservoir itself has a wide mouth and little handle so it’s super easy to fill it up from a water source. 

Perhaps our favourite thing about the Platypus Quickdraw is that you just need to squeeze it in order to dispense filtered water, with no sucking required, and that aspect of it makes it very useful for group use and for preparing water for cooking.

The filter couldn’t be simpler to clean. All you need to do is quarter fill a compatible reservoir with clean water, attach it to the cartridge and shake vigorously for 30 seconds for a clean filter and good-as-new flow rate. 

Bear in mind that you can by both the reservoir and Quickdraw together or separately.

Selected for the Outdoor 100 2021/22. Here’s our full Platypus Quickdraw Water Filter review.

9. Sawyer Mini Water Filter

Price: £22
Weight: 57g
What we like: good value, very light and convenient
What we don’t: flow rate slows with use

The cheapest and lightest option in this round-up, the Sawyer Mini is a tried-and-tested water filter used by travellers and adventurers across the globe. It provides 0.1 micron absolute filtration, meaning it will remove turbidity as well as bacteria and protozoa, but not viruses.

As a personal filter system it works well, though the flow rate is not as high as some other filters, and you have to flush it regularly to prevent clogging. These limitations can be frustrating if you need to filter a lot of water quickly, e.g. for a group camp.

Still, the Sawyer’s versatility and low cost meant that it recently made it into our list of best value budget outdoor gear. We still maintain that it is possibly the most useful bit of wild camping kit you can buy for twenty quid and some change. It will last for up to 100,000 gallons too, making it exceptional value for money.

10. MSR Trailshot Microfilter

Price: £40
Weight: 142g
What we like: good value, innovative design, useful for water sports
What we don’t: flow rate slows with use

The MSR Trailshot is a small, simple filter that is ideally suited for fast and light adventures or trail running. It is best used to treat water on the go, though at a push it can also be used to fill your water bottle. When first released it was one of the lightest options on the market. Since then, smaller and lighter filters have emerged, though the Trailshot is still one of the most durable, robust and best personal water filters out there.

The flow rate is pretty good, and backflushing to keep the filter clean is very easy. It’s simple to use too. You just dangle the hose in the chosen water source, give the hand-held plastic pocket a squeeze, and voila – one big gulp of clean drinking water.  The design reaches its limitations if you want to filter larger quantities of water quickly though.

Read our full MSR Trailshot review

You May Also Like:

Best Down Jackets Reviewed

Best Approach Shoes Reviewed

Best One Person Tents