Walking Equipment and Accessories

MSR AutoFlow XL Gravity Filter 10L | Review

A lightweight, packable and durable water filter that’s hugely convenient for multi-day camping trips

Why We Chose The MSR AutoFlow XL Gravity Filter 10L: innovative, effective, packable.

When you’re thinking about drinking water straight from the source you should always be considerate of its cleanliness. Some people will choose to take the risk and drink without purification or filtration, but it’s certainly more advisable to take precautions. You should never rely on the apparent clarity of the water – viruses, bacteria and dissolved metals will almost always be invisible to the naked eye.

“You should never rely on the apparent clarity of the water – viruses, bacteria and dissolved metals will almost always be invisible to the naked eye.”

Of course boiling is the number one way to filter out water, but sometimes fuel is on limited supply when overnighting, not to mention that it also takes a long time to boil even just a couple of litres of water. And this is where water filters like this come in.

The AutoFlow XL filter from MSR cleverly utilises gravity to filter out bad stuff from your water source. Using a 10-litre reservoir that’s hung from, say, a branch or fence post, it’s large enough to supply water for two people for an entire day.

The secret is in its hollow fibre technology. This involves a bundle of spaghetti-like straws, each dotted with microscopic holes that are big enough for water molecules to pass through but too small for nasty things like bacteria, protozoa and dirt.

Simply with the use of gravity, water will flow and filter through these at the rate of 1.75 litres per minute. Granted, that’s slower than what’s offered by most pump-actioned filters, however this has the benefit of being lighter, more packable, and capable of storing and carrying water. It’s built rugged too, using a tough PU film bladder with RF welded seams and smooth, rounded edges.

A strap is included with the AutoFlow XL to allow for easy carry and hanging. Photo: Chris Johnson

The reservoir holds 10L. Enough water to supply two people for an entire day. Photo: Chris Johnson

If you’re in an area with potential waterborne bacteria or metals in the water then it's essential to filter your water. Photo: Chris Johnson

There’s a very simple but effective way of controlling the flow, using just a little clip on the hose that you pinch in to limit the rate or halt it altogether. A cap seals the end of the hose, and this has a clever little adapter that lets you fasten some types of bottles securely onto it. Cleaning it out is easy as well, all you need to do is backflush it by flipping around the filter unit.

If 10 litres is overkill for you, there’s also a 4L option out there from MSR which, as you can guess, is even lighter.

Ultimately, we’d say this is an excellent addition to a wilderness camp, or for any expedition basecamp.

Tester’s Verdict

Will Renwick, Outdoors Magic Editor

“This is very well designed – it makes safe camp hydration effortless. First of all, the wide opening makes gathering water easy, whether that’s filling it from a tap or waterfall, or scooping from a stream. Then, the filtration process is essentially hands-free. You can just kick back and let it do all the hard work. The only hard bit is finding the right place to hang it, and if you’re, say, on a windswept moorland, some improvisation with your tent or trekking poles is required.

“In terms of durability and reliability, I haven’t had any problems; it seems tough and the rolltop is certainly watertight. 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.”