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SteriPEN: Ultraviolet Water Purification

Way back in 1998, when I took my first backpacking trip to Europe during the peak of summer, I quickly developed a love affair with the large 1.5-liter bottles of water.

One or two of them per day was sufficient to keep me hydrated while getting lost in Rome or Paris.

And because the tap water was by and large safe to consume, I was also able to refill them.

Fast forward 10 years, and I'm visiting one of the poorest countries on the planet, Nepal, and feeling guilty within the first few hours of arriving due to the amount of crumpled plastic bottles piling up in my hotel room.

Recycling efforts cost money and remain the domain of more industrialized countries.

The alternatives, as I knew them, were steady ingestion of iodine to purify the definitely-not-fit-to-consume tap water, or filtration systems that looked too confusing to bother with.

Recently, however, I learned about another option.

A local stream
A local stream

SteriPEN is a portable water purification device that uses shortwave germicidal UV light to disinfect water. Sounds cool, right?

This type of light disrupts the DNA of microbes in water within seconds, ensuring they cannot reproduce, which saves you the hassle of getting ill.

Collecting water to purify.
Collecting water to purify

To try the device, I walked to a small stream near my home and filled a 0.5-liter bottle (16 fluid ounces) with water to zap. 

The maximum amount of water that can be treated at once using the SteriPEN Traveler, which is the model I was testing, is 1 liter (32 fluid ounces). 

The instructions indicate that the device should only be used with clear water. 

If the water is brown coming out of the faucet (as I've sometimes encountered abroad) or muddy, then it needs to be pre-filtered using a more traditional method (like a coffee filter or t-shirt) first.

The SteriPEN Traveler is about the length of a toothbrush.
The SteriPEN Traveler is about the length of a toothbrush

Once I got the water sample home, I loaded up the SteriPEN with four AA alkaline Duracell batteries. 

It's worth noting that the instructions strongly emphasize the use of Lithium or NiMH batteries, as they last longer, and can yield up to 200 one-half liter treatments.

I pressed the button on the handle once, and a red light started flashing. 

The batteries I'd put in weren't giving the device enough juice.  I switched them out for newer Duracell batteries and clicked the button again. 

This time it flashed green, which was the “go” signal to insert the device in water.

The SteriPEN at work on a 1/2 liter of water.
The SteriPEN at work on a 1/2 liter of water

I plunged the SteriPEN Traveler into the bottle of stream water and the UV lamp turned on almost immediately after the metal water sensing pins made contact. 

Next, I swirled the lamp around in the water bottle in a clockwise motion so as to ensure the water gets mixed up and is equally treated.

This step is in accordance with the instructions. 

After about 30 seconds, the lamp turned off and the LED indicator light on the handle turned green. 

This indicated the treatment was complete.

I removed the SteriPEN, dried off the lamp, and put its plastic cover back on. I took a sip of the treated water.

It tasted of soil, but that was to be expected.

You might be wondering how I know the water is safe to drink. 

At the end of the day, I know it's safe because of the science behind it, which is the same way I know dropping iodine in my water bottle while trekking in the Himalaya is safe.

If that's not enough for you, then take heart in the testing and certification the product has undergone:

SteriPEN products have been tested by the Water Quality Association (WQA) against the US EPA Microbiological Water Purifier Standard. SteriPEN has received the WQA's Gold Seal, certifying that SteriPEN purifies water safely and effectively.

Still doubtful? 

How about a long list of testimonials from people not just drinking stream water from their neighborhood, but from taking SteriPEN on expeditions to Mt. Everest and thru-hikes of the Appalachian Trail.

In the dark, the UV light glows brightly as it destroys the DNA of illness-causing microbes.
In the dark, the UV light glows brightly as it destroys the DNA of illness-causing microbes

There are 13 different ways the LED indicator light on the handle can blink, each of which signifies something different, such as battery and lamp warnings, so it may be necessary to carry the instructions with you. 

It's worth noting that battery performance may be adversely affected at temperatures below 32F/0C. 

A back-up solution (such as iodine tablets) if you are hiking or camping for extended periods of time, or in especially cold weather, would also be a good idea.

The device itself is lightweight, but the addition of four batteries does give it some heft. 

If I were to take one on an extended trip, I would choose the Traveler mini which only takes two batteries, and purifies up to 100 liters of water.

Overall, I found the SteriPEN extremely easy to use, and I look forward to taking it on my next trip abroad where I can put it to greater use. 

In the process, I'll be saving money, and reducing the amount of plastic waste I leave behind.


SteriPEN is a current sponsor of Go Backpacking, and I received a complimentary device for the purpose of writing this review.  The opinions are mine.

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Tuesday 31st of August 2010

you should also look at ISTRAW kills all waterborne bacteria and parasites 99.9999% and upto 500 litres used in Thailand didn't get delhi belly once and did my bit for pollution by not using plastic bottles


Thursday 6th of May 2010

Yup. Parasites = microbes.


Thursday 6th of May 2010

Yup. Parasites = microbes.


Thursday 6th of May 2010

Great review. This is definitely a tool I'll keep on my list if and when I head to less industrialized countries.


Thursday 6th of May 2010

This is the same technology many water treatment plants - ie, the places where your tap water is produced - are using now. The older method of disinfecting water with chlorine is, in many cases, being converted to using ultraviolet light. Instead of actually killing bacteria, it renders them sterile and unable to reproduce in your gut. If you drink tap water, chances are you already are drinking UV-treated water. Of course, UV does nothing to get rid of the soil and other sediment in the water.

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