UV Water Purification
SteriPEN Water Purifier
Zap water bugs with UV light
Stick the SteriPEN unit into a glass of water, turn it on, stir it around, and in 45 seconds you have killed any bacterial contamination, leaving you with clean safe drinking water.
It is a great way to discreetly purify the glass of water at your table in a third world restaurant, and has many other uses too.
Part 1 of a series on SteriPEN products. Part 2 reviews the Traveler and Adventurer models, Part 3 reviews the solar charger.
The SteriPEN is a space age unit that purifies water quickly and simply, using UV light.
It is compact, light weight and easy to use, and is probably the most effective solution to ensuring the water you drink is safe.
Who Needs a SteriPEN
Hikers and campers
If you go hiking in the backwoods, you'll probably take some sort of water filtration device with you. We all need lots of water, and it is, alas, both bulky and heavy to carry with us.
Unfortunately, those lovely looking fresh country streams are often dangerous to drink from, due to the presence of 'coliform matter' caused when runoff water from wildlife excrement contaminates the water with dangerous and potentially lethal bacteria.
A Steripen is small and lightweight and a great way to ensure you can enjoy safe drinking water when hiking.
One of the blessings of our modern lives is that we have reliable safe water freely flowing from our taps at home (but see the next point). This is not nearly so assured in the rest of the world, and treating the water you use, even for brushing your teeth, in your hotel room and elsewhere with the Steripen can ensure your travel pleasures aren't disrupted by inconvenient and sometimes serious illnesses from water-borne pathogens.
An unexpected danger can also lurk, in some countries, in supposedly safe bottled water. In some countries, there are no quality standards for bottled water and you might find yourself paying a premium for water no better than what comes out of the tap. The Steripen can be inserted into a bottle of water to sterilize the water before you drink from it.
Because the Steripen is small and simple to use, it can also be used to discreetly purify a glass of water given to you in a restaurant when you're unsure how safe the water might be.
Everyone for their Emergency Kit
What would you do if your city's water supply was disrupted? Perhaps an earthquake, or an act of terrorism, or system failure might suspend one of life's essentials we take for granted in most western countries - the reliable flow of safe water through our taps. Indeed, simple mistakes have also disrupted water flow or water purity, sometimes for days at a time, and in some of the world's most developed cities.
If you like to be prepared, a SteriPEN is an excellent addition to your Emergency Disaster Preparedness Kit. It has a virtually unlimited shelf life (many regular water filters expire after a few years whether used or not) and as long as you can feed it batteries, the 5000 uses per replaceable lamp unit give you plenty of pure clean water in an emergency.
The Steripen is sold attractively packaged in a plastic cylinder. Inside is the unit itself, which comes complete with a strong protective sleeve to fit over its lamp when not in use, plus a nice carry pouch. A set of well written instructions and warranty/registration card complete the package.
The Steripen needs four AA batteries, but, alas, no batteries are supplied with the unit. You don't get much for your $100 these days.
Although skimping on batteries, the manufacturer is generous with the warranty, offering a 'limited lifetime' warranty. In the fine print, it reveals you must send in the registration card to qualify for the warranty, and the warranty is offered to the original purchaser only.
Because the lamp must be replaced every 5000 uses, the warranty of course covers the lamp only for its 5000 use life, but the body warranty is unlimited.
The unit, complete with protective cover, weighs 3.6 oz. Add a set of batteries and you've about doubled the weight.
How it Works
The Steripen uses ultra-violet (UV) light (better to use the term 'radiation' rather than light, perhaps) to sterilize the water. UV light is the same type of radiation that causes sun-burn, and, in large doses, skin-cancer. The same dangerous properties of the light are put to good use with the Steripen to simply kill any bugs and germs that might be in the water.
UV radiation is used by many town water supplies to sterilize their water. It is an accepted, safe, and reliable solution, and although we're using the term 'radiation' it is nothing like radioactive radiation and water that has been exposed to UV light is totally safe in all respects.
Although direct UV light is dangerous to people as well as to bacteria, by a happy trick of nature, the UV light is completely contained within water, and so you're at no risk when using the Steripen. You can see a blue glow, but this is not UV light (which is invisible) but visible light that is also generated at the same time. More than 90% of the output of the unit is in the form of invisible UV light.
The Steripen does not neutralize any poisons or other bad chemicals. It kills living things, but doesn't do anything to inert poisonous substances.
Neither does it precipitate out any suspended solids, such as in a glass of muddy water. In fact, if the water is not clear, the UV radiation does not penetrate as efficiently through the water and the Steripen will not work as reliably. For this reason, the instructions say to only use it with clear water, and if the water is muddy, you should let the water settle first, or pre-filter it.
The Steripen has two settings - one for up to 16 ounces (one pint) of water, the second for up to 32 ounces (one quart). You simply choose the appropriate setting, turn it on, stick the light tube 'wand' into the water, stir it around until the UV light goes off, and you then have pure safe water to drink.
Electronics inside the unit compute how long to operate the UV lamp for, and generally it is about 45 seconds for 16 ounces and 90 seconds for a full 32 ounce quart of water.
The unit also counts how many times it is used. Because the UV light tube wears out over time, when the unit has been used 5000 times, it gives an error and requires you to replace the light tube. This involves returning the unit to the factory, where they replace the assembly and return the unit for a $40 fee. The unit gives a warning at 4900 uses so you can plan for the replacement at a convenient time.
Using the Steripen
Using the Steripen is as simple as it should be.
Because you need to fully immerse the light tube, there should be at least 2½" of water in the water container, although if the container were flat and wide, you could hold the Steripen on its side to fully cover it.
You push its button, then immerse it in the water. The unit senses when it is in the water and activates.
As well as generating the UV light which is invisible, it also generates some visible light so you can see that the unit has started to work (and, more to the point, when it has completed its task, too).
Stir it around while it is radiating, and when the light turns off, check that the indicator LED shows green.
And that's all you need to know and do. Almost instant safe drinking water is the result.
I was concerned that the glass capsule surrounding the light might break, but Miles Maiden, Steripen's inventor and company President, explained the capsule is actually made from strengthened quartz, 1/10" thick. It is strong and unlikely to break during normal usage, which is just as well, because the warranty unfortunately excludes glass breakage.
When not in use, a strong plastic sleeve surrounds and protects the quartz tube.
Because ice cubes are often not perfectly clear, the UV light may not be able to shine all the way through ice and so you should not have ice in the water when purifying it.
The Steripen uses a lot of power and is fairly hard on batteries. A set of four regular AA alkaline batteries will be good for about 20 - 40 uses, each for a pint of water.
If you get the longer life Lithium type batteries (single use, not to be confused with Lithium Ion rechargeables), these can give you up to 140 cycles.
Rechargeable batteries are probably your best choice if you plan to use the unit regularly. A set of modern high capacity NiMH batteries (such as the ones we review here) can be expected to give 150 uses per charge. The cheaper NiCad type batteries will give fewer than 20 uses per charge and probably shouldn't be used.
The Steripen tells you when the batteries need replacing (the LED flashes red quickly).
The Steripen compared to other products
If you're comparing the Steripen with other ways to get safe drinking water, it is first essential to compare it accurately with similar products.
Many devices are sold as water filtration systems, but these are not the same as an EPA approved water purification system (the Steripen has been independently tested and passes the EPA's purification parameters).
The best water filtration systems have a maximum filter size of 0.2 microns (a micron is a millionth of a meter) and are effective against bacteria (which range in size from about 0.2 microns up to 10 microns) but are ineffective against viruses which are much smaller (0.004 - 0.1 microns in size).
A purification system is effective against both viruses and bacteria. Viruses (eg hepatitis) are every bit as dangerous as bacteria, and so you really need a full purification system rather than the partial solution presented by a filtration system.
Filtration systems not only don't protect you from viral infection, but are also can be more expensive than the Steripen, bulky, and awkward to operate (probably requiring you to pump water forcefully and slowly through a filter). Filtration systems are also prone to clogging, and either need regular replacing or cleaning.
The lowest tech approach to purification is to simply boil your water for several minutes. But this requires a heat source and suitable container to boil the water in, plus the patience to wait until the water has cooled again before drinking it.
The most common purification method is to add chemicals to the water that will kill the viruses. Chlorine or iodine tablets are added to the water, and after letting it stand for a while (up to four hours in some cases) you end up with water that is safe to drink, and which hopefully doesn't taste too bad.
The Steripen is generally quicker, easier, and more portable than all these other solutions.
Which SteriPEN Model is Best for You?
When this review was first written, in December 2004, this was the only model SteriPEN available.
Since that time, not only has the price of the original (we term it the 'Classic') SteriPEN dropped from $150 to $99.95, but the manufacturer has also released a new smaller model, currently priced at $130. All models work identically, the only difference is their size and price. We review the new Adventurer and Traveler model SteriPENs here.
The Classic SteriPEN is less expensive, but is also bulkier and heavier than the new Traveler and Adventurer model SteriPENs.
With airlines increasingly reducing the amount of luggage you can take with you for free, and with weight and space considerations also being critical for backpackers, the smaller and lighter units more than justify the $30 extra cost for most people. But if your main use for the SteriPEN is to have it as part of your disaster preparedness kit, you might prefer the Classic SteriPEN which uses very common AA batteries.
Where to Buy
Steripen is manufactured by Hydro-Photon in the US. They have retail distributors spread around the US, and these days the device lists for a very good value of $99.95 (it was originally $150). Hydro-Photon forbid discounting.
Travel Essentials stock the full range of SteriPEN products and accessories, and offer the Classic at this price, with no sales tax and give you free shipping, which is probably the best deal available. And should you want to buy more than one, they offer a $5 per unit discount on multiple orders. They also offer the Traveler and Adventurer units at $130 each.
Chances are, before reading this article, you didn't know you needed a water purifier, or what the difference is between a water filter and water purifier!
But whether you now feel this might be useful when hiking outdoors, when traveling overseas, or just to keep in your household emergency kit, you probably now agree that a Steripen is a very convenient and effective solution to the problem of how to ensure you have reliable access to safe drinking water, wherever you are.
The Steripen is now a regular part of my international travel kit. Recommended.
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