So, you've drunk all your water. And, there aren't any shops nearby. Or houses. Or people. What do you do?

Well, if you've got a portable water purifier, one thing you don't need to do is panic!

The Steripen Classic 3 UV Water Purifier is the perfect companion when exploring the wilderness - on bike or foot. It's light-weight, and simple to use.

Dunk the business-end into water. A mere ninety seconds later, the water is clean and safe to drink.

Steripen is a battery-powered portable water purifier.
Steripen is a battery-powered portable water purifier.

About Steripen

Steripen is owned by Katadyn who bill themselves as "the market leader for portable, personal water treatment systems and products for the outdoor and marine industries".

Their products are used by many international aid organisations as well as the military, which suggests decent quality and reliability.

The Steripen Classic 3 UV Water Purifier eliminates any bad stuff by using UV light to zap impurities and bacteria dead.

This portable water purifier is not big at all. It's 7.3 inches long and 1.7 inches thick. And, it weighs a total of 178 grams.

The bundle includes the Steripen with a pre-filter cap and carry pouch.
The bundle includes the Steripen with a pre-filter cap and carry pouch.

The Steripen comes with a soft-shell case and a pre-filter bottle lid. The filter lid works by screwing it onto a water bottle before taking water in. As you take water into the bottle, the filter prevents any larger pollutants from getting in.

The Steripen is battery powered, running on alkaline, lithium or NiMH AA batteries. The latest iteration is the first Steripen to work effectively with alkaline batteries, making it universally usable. Walk into a shop in the middle of nowhere in Western Sahara (one of the least populated places on earth) or the Outback in Australia and you'll find AA batteries.

Batteries may not be your issue though if you're out of water in Western Sahara or the Outback, as they're both deserts. By definition, finding water to purify will be problematic...

But, digressions aside. The Steripen Classic 3 UV Water Purifier treats half a litre of water in 48 seconds and up to a litre of water in only 90 seconds.

How does it work?

Well, without getting too technical (because I don't know enough about UV water purification to get technical), you simply put the pre-filter lid onto a water bottle. Then, dunk a bottle into Mother Nature's flowing streams, rivers or lakes and fill the bottle.

Next, take the pre-filter off and put the business end of the Steripen into the water. Hit the button once to purify a half-litre of water. Or, hit it two times for double the fun and clean a full litre of water.

Then, wait as the Steripen Classic 3 UV Water Purifier starts "destroying all the little critters that can make you sick"! Or, to put it another way - ultraviolet (UV-C) light rays safely purify clear water by destroying 99.9% of protozoa (including Giardia and Cryptosporidia), bacteria and even viruses.

After 90 seconds, a small bulb glows red or green indicating the successful completion of the treatment process. I'm presuming the red light means 'go straight to jail and do not collect £200.' Or, simply, try again. I'd try it again if my options were either red or green and I got a red light.

The Steripen can purify a litre of murky water in 90 seconds.
The Steripen can purify a litre of murky water in 90 seconds.

The Steripen Classic 3 UV Water Purifier is the only portable water treatment device to have received the Water Quality Association's Gold Seal.

According to Katadyn, the Steripen's UV lamp has a lifespan of approximately 8,000 uses. Steripen promises to replace the device once it hits 8,000 uses.

Test conditions

I'm plodding around north Africa for the winter time. I wanted the water purifier for more autonomy and self-sufficiency while cycling. Cycling around as much as I am and for as long as I plan to, I don't want to get caught short not having water. There are certainly plenty of opportunities to test the Steripen's capacity to kill bacteria in the water here.

On and off the bike, I was able to use the purifier.

I did a short two-day walk with the Steripen packed. Even while staying in accommodation in a town on the coast, I didn't trust the water. Well, I didn't trust the water because the hostel owner said everyone who drinks the water gets sick. The water was coming out of the tap cloudy.

So, the purifier came in handy in town, close to town and far from town.

With the Steripen in my kit bag, I had peace of mind that I had choices available to me when it came to a fairly important area of survival. Having a purifier also means it's not necessary to purchase bottles of water adding to plastics waste. Finally, packing the Steripen and purifying water when needed/ available is far more efficient than lugging around litres and litres of heavy water.

The purifier certainly lends a level of comfort when bikepacking or going out on a longer hike in uninhabited areas. Overall, I found the purifier easy to use and effective. I didn't get sick once!

The Steripen comes with a storage pouch.
The Steripen comes with a storage pouch.
The blue cap protects the UV wand when not in use.
The blue cap protects the UV wand when not in use.
Pre-filter cap removes particulates before the UV wand does its work.
Pre-filter cap removes particulates before the UV wand does its work.

On top of its effectiveness at providing me with potable water, the environmental factor can't be ignored. Rather than resupplying from buying more bottles and more plastics in shops, having the purifier means I could pull water straight from the natural supply chain!

Of course, weight is a big issue for us cyclists. The Steripen is only 178 grams. That is considerably lighter than the alternative - carrying litres of water if you didn't have a water purifier.

If I could suggest any area of improvement, it would be to have a carry case for the Steripen and filter. But, I get that the key here is the Steripen and not the filter. I'm sure not everyone is going to use or even bring the filter with them. But, if it's going to come as a package, having the option of keeping it as a package when in use or when in storage at home would be great.

Ease of use

The Steripen is simple to use.

Before this trip, I'd never used a water purifier. So, before I left and ended up shit's creek (figuratively after failing to correctly purify water from that creek in a literal sense), I read the instructions at home. I did a few trials to make sure I was comfortable with using the purifier. It was overkill, the device is quite easy to use. But, 'fail to prepare...'

Stick on the filter lid, soak up some water and then use the purifier to zap bacteria. There's even an accompanying light show to indicate where in the process of purification you're in:

  • Step one - put the UV rod into the water and push the button to start. Not much light

  • Step two - as the Steripen moves through its cycle of purifying the UV wand emits more and more light

  • Step three - the end of the purification cycle activates a green or red light

Watching the UV wand's glow increase is slightly hypnotising. There is also a slight light-sabre-ish, Star Wars vibe to it all. Which is not a criticism by any means.

And, even though my whole contribution to purifying was to push a button and hold the Steripen in place, it somehow felt like a personal accomplishment every time the light flashed that the purification process was finished!

Water great deal

The Steripen retails at £75. For comparison, a product like the LifeStraw - which allows you to drink directly from a dodgy water source, but can't be used to fill a bottle - will set you back about 25 quid and filter about 1,000 litres of water. That means to match Steripen's 8,000 purification cycles before Katadyn will replace your Steripen, it's going to cost around £200.

They are different products, and of course you have to factor in the cost of batteries to keep the Steripen in power, but essentially the Steripen looks good value for a product of this nature.

Speaking of batteries, Katadyn advise you can expect to get 50 litres out of a set of four alkaline batteries. NiMH performance varies by mAh rating: 2300 provides about 100 litres, while lithium batteries are the most economical choice.


A big part of an adventure is balance. When you go out there, you need to be a little more autonomous and provide more for yourself. There's not going to be a corner shop in the middle of nowhere.

And, for the adventurous types out there, sourcing and purifying water so it's safe to drink is crucial.

Katadyn's Steripen Classic 3 UV Water Purifier is the tool to avoid drinking contaminants. It's simple to use, packs away small, is environmentally friendly, way more efficient than carrying litres of water, provides peace of mind, can be used anywhere as it is compatible with multiple types of batteries, and basically comes with a lifetime guarantee. And, it puts on a light show!

Steripen Classic 3 UV Water Purifier - £75.00 from Lyon Equipment.

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