In the comments of a water purifier review I made a while ago a reader mentioned the SteriPEN. The SteriPEN is a water purifier that completes its task using UV light. This sounded too cool to pass up so I decided to review the device. After a spring, summer, and fall of very mixed use I’ve been able to figure out where, in my arsenal of gear, this purifier fits.
SteriPEN Water Purifier Review
The SteriPEN’s concept is really neat. By zapping your water with UV light you kill everything in it. To quote the user manual:
“SteriPEN? uses short wave germicidal UV light to disinfect water. This range of UV light destroys the DNA within bacteria, viruses and protozoa,rendering them unable to reproduce and therefore, harmless. UV treatment is a proven and long-accepted method for disinfecting drinking water.”
The device uses a dosage of UV light that is big enough to kill everything in your water but not big enough to hurt the human using it. The device is roughly the size of a medium sized flashlight (with a pointed tip) and is quite comfortable to hold and use. It is well built and rugged and I haven’t had any problems with it thus far.
The SteriPEN uses 4 AA batteries. While I applaud the designers for choosing a common battery type the four batteries add a lot of weight to the device. It would be nice to see them cut down the weight of the device with the batteries in it. According to SteriPEN your normal off the shelf Alkaline AA’s will give you 20-30 half liter doses, Lithium 130, and NiMH 150. Not great for the Alkalines but otherwise decent performance with the other battery types.
Using the SteriPEN is quite easy. Fill up your water bottle, press the button once or twice (once for half a liter, twice for a full liter), put the glass end of the device in the water, and swirl. When the light turns green (flashing or steady depending on dose) your water is safe to drink! From what I’ve seen this is by far the fastest way to treat a liter of water in the field.
One of the biggest struggles for water purifiers is taste. By using UV light the SteriPEN can boast absolutely no change in taste. This is quite an advantage over chemical based treatments.
One of the few drawbacks of the SteriPEN is that the water you treat must already be clear. To get around this the company also sells a filter that screws onto a full sized Nalgene (1 liter). The filter is quite handy and works well. But this adds even more weight to the SteriPEN’s total package.
Aside from being a little heavy, the two largest issues I have found with the SteriPEN are the time it takes to treat more than one dose, and its inability to treat more than 1 liter at a time. For each liter you treat it takes approximately 90 seconds of work (stirring the bottle). In one situation this summer I was treating water on a hiking trip for three people. Each person was using a multi liter hydration system. It would take us approximate 15 minutes of stirring and transferring from a Nalgene to the water bladders each time we wanted to water up. Mind you the water was immediately ready to drink after that 15 minutes. Immediate water consumption is not often a huge concern though.
My SteriPEN has treated tap water in Peru, river water in the Amazon Basin, stream water in Maine, and countless streams in Newfoundland. Not once in any of these situations did I become sick from consuming contaminated water. So from all I can tell the device does in fact treat the water as it claims to.
It’s taken me a while to figure out where and when the SteriPEN goes in my pack. I found the device very useful traveling and treating clear tap water. I was able to save a few bucks on buying bottled water and it only took a few minutes a day to treat what I needed. I’ve also found the SteriPEN to be very useful on day hikes. On day hikes the extra weight is not really a big deal and the ability to drink treated water in less than two minutes is a definite advantage over other treatment options. The SteriPEN didn’t make the cut for me on long multi-day backpacking trips. The extra weight and its inability to treat multiple liters at once make it not as attractive as my MIOX for those long trips in the back country.
Overall the SteriPEN is a great purifier for day hikes and traveling but not well suited for long backpacking trips.