SteriPEN Ultra Water Purifier Review

Using a Steripen Ultra water purifier will remove all contaminants, without the use of chemicals. A normal water filter will only remove waterborne bacteria and protozoa, but not viruses.

This Product Appeared on Our 5 Best Water Purification Pens article.

Steripen Ultra will combat all three microbes that could be lurking in the water you’re about to drink. That also includes chlorine and any harmful metals that can’t be seen by the eye. 

Without a water purifier, you can’t guarantee that your water is pure and fresh. Especially if you’re out on a hiking trail or camping out and have no access to safe drinking water.

Yet, all you need to do is carry around a Steripen Ultra, and you can be confident all your water will be safe to drink. In this review of the Steripen Ultra water purifier, you will soon understand why you need this little gadget on your adventurous travels.

SteriPEN Ultra Features

SteriPEN Ultra Specs
Size7.3 x 1.3 x 1.6-inches
Power1 USB Rechargeable Lithium Polymer battery included.
Treatment Volume15000-liters of water.
CertifiedWater Quality Association (WQA) standards.

When you’re traveling, there’s one important item you should always take with you, and it takes up very little space in your luggage. This small gadget means you can be sure that the water you’re drinking is completely safe, anywhere, anytime.

No more iodine tablets to clean your water. Let the Steripen Ultra kill 99.9% of bacteria and viruses instead. This mobile water purifier works by using UV rays. 

What’s more, you can simply pop the charger into your USB port for recharging the battery-operated water purifier. Battery and charger cable is provided.

One-click will clean up to ½ liter of water in under a minute. Then add a further click for every extra half-liter of water. 

The unit has a self-illuminating OLED display. You can monitor the water treatment success rate, battery status and keep track of how many times you’ve used it. 

To learn more about all the great features of the Steripen Ultra, have a look at the online instructions leaflet:

Steripen Ultra Popular FAQs

Why use a water purifier?

Water purifiers are an essential tool if you’re out and about and don’t have a safe supply of drinking water. With a water purifier, you can be certain the water will not make you ill.

There are three main contaminants in water, that can be a danger to humans. Protozoa, which includes mold and fungus. Bacteria, particularly waterborne. Viruses, which are microorganisms that are harmful to humans.

How long does the SteriPEN Ultra battery last?

One full battery charge will give you up to 50 clicks. Allowing you to purify up to 25 liters of water for every charge. The rechargeable battery has approx. 300 charge cycles.

It’s recommended that we drink approx. 3.5 liters of water per day. That means you will have approximately 7-day’s supply of pure water, per person, in only 1-charge.

How do you know if SteriPEN Ultra is on?

For this function, you will use the environmentally friendly OLED (Organic Light Emitting Display). Once you click the on/off button, you will see a 15-second green light to let you know it’s is switched on. You will know the progress of purification by the colored lights, such as:

– Slow Flashing Green Light indicates “in progress”.
– Green light on but not flashing indicates “complete”.
– Red light indicates battery life.

Once submerged in water, if you have no visible lights then your pen is not working. Should this happen, it means it’s unsafe to drink the water as it isn’t treated. 

Does SteriPEN ultra kill viruses?

YES – It kills all bacteria, protozoa, and viruses too. It’s best used on clear water. You can treat murky water too, but it may take longer. See the pdf instructions leaflet that we’ve provided in this article.

To understand how harmful germs in water can be, have a look at this useful article produced by the CDC (Center for Disease Control).

How to Use The SteriPEN Ultra?

Time needed: 2 minutes.

Here’s a quick 5-step guide on how to use the SteriPEN Ultra to purify water:

  1. Remove Lamp Cover

    Always remove the lamp cover first.

  2. Activate SteriPen

    When you first turn on, the green light will flash on for approx. 15-seconds, this is not a treatment. Before immersing in water, click on/off button once for each half liter of water you need to treat.

  3. Purify Water

    As the Steripen goes into the water, it will set the UV lamp in motion and the green light will flash. Stir the Steripen around in the water to mix it up a little.

  4. Know When The Process is Done

    Once the purification is complete, the green light will stop flashing but remain on. You will also have a smiley face in the OLED to indicate your water is ready to drink. Any red lights indicate battery warning, so don’t drink the water as it will not be properly cleaned.

  5. Switch Off and Dry 

    When finished, dry the lamp section and replace the lamp cover for protection.
    If you want to see the Steripen Ultra in action, then watch the Steripen Ultra instructions on their own video below.


The older version of this model is the Steripen Freedom. Whilst it was lighter in weight, it could not perform as many water treatments. The newer Steripen Ultra is also less expensive, even though it’s the updated model.

The weight difference is because the Ultra has a better battery life so the battery is most likely slightly heavier.

The Steripen is quite a unique piece of life-saving equipment. It can simply be inserted into your water bottle, so long as the bottle has a wide enough opening.

Have a look at our CamelBak insulated water bottles. They are a perfect fit for the Steripen, with the lid removed.

If you’re planning an outdoor expedition, then you may also want to take along a good hiking backpack. We’d like to help you plan this. That’s why we’ve reviewed the Thule backpack.

Including a Steripen Ultra on any journey that you’re planning, is not only a sensible option but could potentially save your life. Particularly so, if you’re going on an outdoor vacation. Clean drinking water is vital for your health.

Many hikers have used other water filters, such as the Wild Peak straws. They can’t guarantee to kill viruses, only the waterborne bacteria, and protozoa. If you’ve read our article on germs in water, then you’ll understand why you’re better off taking along a Steripen Ultra. This is the only way to be confident your drinking water is fully for sterilized.

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