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Steri Pen
Gear Review

Steri Pen

Steri Pen

Page Type: Gear Review

Object Title: Steri Pen

Manufacturer: Hydro-photon

Your Opinion: 
 - 7 Votes


Page By: Dean

Created/Edited: Feb 1, 2007 / Feb 1, 2007

Object ID: 2479

Hits: 9477 


Product Description

The newest kid on the block is the SteriPen water treatment. This is so promising I even bought a unit that I can't wait to try out this coming year. Using UV light, the SteriPen functions to sterilize (purify)water
that you used to use a manual filter on.

It is compact, light weight and according to the instructions easy to use.

A Steripen is small and lightweight and a great way to ensure you can enjoy safe drinking water when hiking. Tourists can also benefit from such a form of sterilizing water.

From the Travel Insider, I have collected this information:
"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.

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 $150 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 $60 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. 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.

Battery Life

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 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 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."

The Travel Insider also offers a lot of other products and information and is a very useful resource.

(My note: we'll see)

Hydro Photon link

In addition to the information offered above by the Travel Insider,
Hydro PhotonLINK TEXT HERE has a page listing information and a slide show and
how to as well as how to locate a dealer.

Pricing: I picked up my unit for $99 but I've heard that a newer improved version is now on the market and may be more money. I will post a review as soon as I've actually used this product.




Viewing: 1-8 of 8

DustianoUnit leaked

Voted 4/5

Thank goodness I brought drops to Chicago Basin too. On my initial run with the Steripen, water leaked into the battery compartment, and in turn the light apparatus. The unit went down... In theory, the system is a great invention, albeit fragile, and if it weren't for my defective unit, would probably perform quite well.
Posted Feb 2, 2007 1:37 am

C-DizzleRe: Unit leaked

Hasn't voted

I'm curious how the water leaked in...Is it necessary to submerge the device to the point where the battery compartment is submerged as well? Or did the water leak in through the parts that should normally be submerged? I may be depending on this device for water treatment on an upcoming trip, and I want to know if I should bring "backup". TX!
Posted Jul 10, 2007 8:43 pm


Voted 4/5

I inadvertently voted above so please ignore it as I haven't used the unit yet. However, here is the thread at NWHikers.net that caught my attention and was the main reason I wanted to try this technology out. SP's own Tazz was the main contributor and is very enthusiastic about how well it has worked for her and her husband.
Read all the entries in THIS THREAD as there are a couple negative experiences with the Steri pen as well.
Posted Feb 7, 2007 6:15 pm

WoundedKneeVery convenient

Voted 5/5

Have "field-tested" a few times, and like it much better than the filters...less bulk and easier to use. Plus, water tastes better than that treated with tablets. I am concerned with fragility, though, so I usually, wrap the device in a garment of clothing.
Posted Mar 14, 2007 12:58 pm

TJ311Worked Great

Voted 5/5

I recently used the steri-pen on a backpacking trip and it performed flawlessly. Water tasted fine. I agree that it seems fragile, I wrapped it inside of a garment and inside my pack.
Posted Oct 14, 2007 4:45 pm

imzadinot so good in the cold

Hasn't voted

We bought this due to the size, weight, and knowing the UV is good for killing most anything (heck, it's used in my lab to sterilize the biohazard hoods in microbiology).

However...we tried to use it two weeks ago (late October) when at Saddleback. It did have new batteries...but, we couldn't get it to work. Finally, after a few attempts...it worked. But...it was scary for a time.

I think that this system is good when warm. If it's cold...using this is very difficult! It's hard to push that button with cold hands. It's also difficult to "swirl" it in the water with cold hands!

It's a good idea...but...
Posted Nov 12, 2008 5:56 pm

dakotaconcreteGood product!

Hasn't voted

I have the updated steripen but I think there isn't much difference between the new and old. Anyway, the product worked great during last years climbing season with the exception of one time when I got bug spray all over the sensor completely rendering it inoperable (I figured this out later at home). I'm glad I had iodine tablets with or I would have been up a creek without a paddle.

Just make sure the unit is clean, it really wasn't hard to screw up, it's not like I sprayed it with dope, it was the remnants from hands while handling it.
Posted May 29, 2009 3:35 am

Brian CGreat with good, clear water

Voted 5/5

For mountain streams and other "clean" sources, I love the steri pen. I've used it a LOT and have never gotten sick. Use lithium batteries to greatly increase the battery life.
Posted Aug 6, 2013 12:06 am

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