Katadyn Steripen Ultra Review

When it comes to finding the best camping water purifier for the backcountry, you have a lot of options. Unfortunately, most of them aren’t quite as fool-proof or convenient as we’d like. All too often, purification systems require you to balance on a rock in the middle of a creek while pumping water or to wait 10 minutes or more before you can take a drink.

Enter Katadyn’s Steripen Ultra to the rescue! Hands down the best UV water purifier for camping or backcountry adventures.

This water purification device uses UV light rather than a traditional water filter, so it promises to eliminate pumping entirely. It can also sterilize a liter of water in just 90 seconds. While different than a traditional filter, the Steripen Ultra is well worth adding to your emergency supply stash as a great add on tool to a traditional filter.

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How Does the Steripen Ultra Work?

The Steripen Ultra uses UV light to purify your water. UV is effective against essentially every type of microorganism, including protozoa and viruses that some other types of water purification won’t eliminate.

Katadyn Steripen Ultra: The Basics


We were extremely happy to find that Katadyn built a relatively thick plastic casing around the Ultra’s UV bulb. It would probably still break if you dropped the bulb end on a hard surface, but in general the casing felt sturdy. We weren’t overly worried about banging the tip against the side of a water bottle or stuffing the device inside our backpack.

We also appreciated that the Ultra comes with a hard plastic sheath that fits over the entire tip end of the device. This locks on securely, and with it on there was little chance that the tip could be leveraged and snapped off inside a backpack.

Over the long term, you should also consider the durability of the bulb and battery. The bulb is rated to treat 8,000 liters before it burns out, which is more than most backpackers and Preppers will need over a lifetime of trips. The rechargeable battery should last longer than the bulb if it is periodically recharged (two or three times per year).

Size and Weight

The Ultra weighs in around 4.9 ounces. That’s pretty light considering it has a built-in battery, but it’s still a few ounces heavier than competitors. Unless you’re trying to build an ultralight backpacking kit, though, we don’t think the weight difference is worth worrying about.

Battery Life

One of the major considerations for any battery-powered water purifier is just long how the battery would last in the field. Getting caught out in the backcountry with a purifier that won’t turn on is downright dangerous.

Katadyn says that the Steripen Ultra can purify up to 50 liters of water on a single charge. In our own testing, we didn’t make it quite that far. The battery ran out of juice after around 40 liters in indoor conditions. It’s likely that battery life will drop further if you use the Ultra in cold conditions during the late fall or winter.

The battery does not charge super-fast either. Charging from an AC wall outlet (via a USB adapter) took close to four hours when starting from fully drained. If you carry a solar panel with you in the backcountry, it could take a full day or more of sun to fully replenish the Steripen Ultra’s battery. Your best bet for trips longer than a week is to bring a portable battery along with you (or solar panel with its own power pack).


At a higher price point than other water filtration options, the Steripen Ultra is not the lowest priced water filtration option. With its great portability and ability to eliminate all viruses, the price is well worth consideration.  FYI - viruses are not often a threat in North America, but there are significant water quality issue in many developing nations.

Using the Steripen Ultra

The main selling point of the Steripen Ultra is convenience, and after giving it a try we have to say that it’ll be hard to ever go back to a pump filter.

To start, you don’t need to be anywhere near a creek to purify your water. You can collect water in your bottle and leave the device behind. Then, rather than try to balance over the creek while purifying, you can find a nice flat area nearby to deal with the purification process.

The process itself is simple, too. Push the power button on the device once if you want to purify one liter of water, and push it again if you want to purify half a liter. Once you submerge the tip of the Steripen Ultra, the UV light will turn on and the small screen will start counting down. It takes 90 seconds to purify one liter or 50 seconds to purify half a liter.

During this time, you’re supposed to stir your water using the tip so that the entire volume is sterilized. This is infinitely better than pumping in our opinion, which also takes at least a few minutes of work. But, stirring for a full 90 seconds does feel a little monotonous.

One minor issue we had with the device was that you can’t pause and then restart the timer. Where the UV bulb tip meets the upper half of the device, there is a pair of electrodes that sense when the tip is submerged. If you accidentally pull these electrodes above the water line at any point while purifying, the screen will display a frowning face and you’ll need to hit the power button to start the 90 second timer all over again. Having the safety feature so you don’t accidentally get UV light in your eyes is important. However, it seems like the timer should just pause and then start again without resetting.

The other thing to note is that the Steripen Ultra can’t purify more than one liter at a time. So, if you typically carry a two-liter water bladder, you’ll also need a one-liter bottle that you can use to purify water. This can also make using the Steripen Ultra as the sole water purifier for a group something of a pain, since you have to sterilize one liter at a time.

Is the Steripen Ultra Worthwhile?

The biggest draw to the Steripen Ultra is that it’s ridiculously convenient. Having the ability to filter water in 90 seconds without standing over a creek or fighting against a filter pump is incredibly nice. Plus, the fact that the Steripen Ultra is effective against viruses means that it’s one of the better water purification options for international trips.

The biggest issues we found with the Steripen Ultra are the battery life and charging time. If you already carry a small portable battery with you to charge your phone or headlamp, you can easily use that to charge your purifier as well. If you don’t want to carry a battery, the Steripen Ultra will still work for purifying water for a single person for up to a week.

It’s also worth noting that UV light has to directly hit any microorganisms in your water in order to kill them. UV rays cannot pass through silt and other particles, meaning that the Steripen won’t necessarily be effective at treating silty water. (To be fair, filters and chemical treatments also struggle with making silty water safe to drink.) You may want to filter your water first if it has silt or other particles that make it cloudy.

With all that in mind, we think the Steripen Ultra is well worth the premium cost and slight weight penalty compared to many competing water filters. It’s hard to put a price on convenience, especially after a long day in the backcountry. The Steripen Ultra offers a level of simplicity and speed that’s been sorely lacking in the water treatment space up to now.

Consider the Steripen as a great investment for outdoor activities or to add to your emergency stash or bug out bag.

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The Simple Prepper