I’ve been looking at water purification systems in preparation for an upcoming Peru trip. Previously I have only ever used chemical purification. Given that the Peru trip will be 12 days, I wanted something which was lightweight and relatively quick at purifying water. Until recently it was difficult to find a filter that could kill both bacteria, viruses, and protozoa, but that has changed with UV filters such as the SteriPEN.
The SteriPEN is a small, lightweight device that emits UV light for 90 seconds (for one litre) when submersed in water. The UV light actually doesn’t kill bacteria or viruses, but renders them unable to reproduce, which is just as good. The SteriPEN Journey pack comes with a plastic pre-filter designed to get rid of any debris in your water source, and should fit any bottle size.
I took the SteriPEN on a 4 day trip to Perquin in El Salvador to test it out. It turned out to be very easy and convenient to use – even with a group of 11 people it was relatively quick to purify enough water – and much easier than hand pumping. A few SteriPen reviews on the Internet mention the dreaded “sad face” or red light error with SteriPENs – I experienced this a few times, and every time it was user error. Typically because I either submerged the SteriPEN in water before pressing the “on” button, or because I accidentally removed the pen from the water too early (or the pen wasn’t properly submerged). After a four day trip, nobody from the group has experienced any illnesses yet (touch wood!).
There were two very minor issues I experienced with the SteriPEN. The first is that the pen itself doesn’t fit very well in standard narrow-necked water bottles. It goes in, but you are unable to stir the water as recommended in the instructions. This is only a minor problem since most hikers are likely to have wider necked bottles anyway (and one is supplied with the system if you buy the SteriPEN Journey).
The other problem was battery usage – I was quite surprised to see the batteries dead at the end of 2 days. With a group of 11 people purifying about 4 litres each, this is way less than the 100 cycles the documentation promises. The batteries were the ones supplied with the system, so perhaps they had lost some of their charge in storage, but this highlights the need to carry spares just in case. The SteriPEN uses CR123 batteries, which can be a bit difficult to find in some parts of the world.
Overall though, the SteriPEN was a very effective system, simple to use, lightweight, and effective. Unlike chemical sterilisation, water taste is not affected, and unlike most filters, both viruses and bacteria are killed.
I originally wrote this review of the Steripen in mid-2012, shortly after I bought the SteriPen Journey package. Since then I’ve used the SteriPen on all overnight camping trips from Scotland to Chile to United States. In this time I’ve never experienced problems with the Steripen system and have never experienced any illness due to bad water either. The battery life concern remains an issue – it would be potentially dangerous if the batteries died mid-journey, leaving you without a sterilization option. However, spare batteries can easily be carried (I usually carry 6 batteries – 2 in the pen and 4 backup) and they consume very little room. Iodine or chlorine tablets would consume just as much space in a pack. Rechargeable batteries and a charger are a sensible purchase though, especially if you will be using the Steripen a lot.