While attending college in Texas, I decided to go hiking in the Hill Country during August with temperatures in the 90’s with high humidity. I underestimated how much water I needed, and ended up eight miles from school severely dehydrated. Since that teaching moment, water has been a high priority for me.


Full Disclosure as Required by the FTC:

The SteriPEN Ultra, as shown in this gear review, was provided to me by Hydro-Photon Inc., makers of SteriPEN.


The Science Behind It:

SteriPEN Ultra uses UV (Ultra Violet radiation) to deactivate the DNA in harmful organisms found in untreated water. Contrary to popular opinion, this treatment does not kill them, rather it stops them from replicating and causing illness. Since UV rays fall outside of the visible light spectrum, SteriPEN added a visible light to the unit to indicate proper working condition.

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How to use the SteriPEN Ultra:

1. Pre-filter your water: the clearer the water (less particulates), the better the SteriPEN will work


2. Make sure the Ultra is charged, and remove the protective probe cover

3. Insert Ultra into bottle of water to be treated

3a. Push gray button once for 1 liter


3b. Push gray button twice to treat .5 liter

4. Swirl the probe in the water to ensure maximum coverage

(Unit will countdown to zero)

Steri button start

* If the conductive prongs are not immersed, the Ultra will automatically shut off


5. Once the countdown is completed, your water is ready to drink!


Powering the SteriPEN Ultra:

With any electronic device, you have to consider your power needs and charging sources. Recently I have been switching over my electronics in my emergency kit to USB (5VDC) power. One of the reasons I like USB (5VDC) charging is the variety of charging configurations available:

When 110 AC Power is available

Steri AC power

12VDC cigarette plug converts to 5vDC USB

Steri plug

12VDC Solar

Steri solar
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My experience showed 3.5 hours charge time with the AC wall charger; 5 hours 45 minutes via USB (computer).

Note: The Ultra uses an internal rechargeable battery that is not user replaceable.

If you prefer a CR123/RC123 or AA battery power configuration, consider the following SteriPEN models:


SteriPEN Adventurer Opti


SteriPEN Classic

SteriPEN Traveler

 SteriPEN Emergency


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Notes & Observations on the Steripen Ultra:

How many uses do you get in one full charge?  According to the manual, the average amount is 50 Liters.

Over a course of a month of testing, I averaged 54 uses per one full charge.

With the Ultra fully charged for each test and selecting the 1 liter option, the results were as follows:

1st test: 54 uses

2nd test: 55 uses

3rd test: 55 uses

I also noted that the battery indicator didn’t appear very accurate. It would show 50% charged  and yet I was on my 50th treatment with 5 treatments left.  The best way to handle this is to have a means to recharge the unit, and disregard the battery indicator.

Over the lifespan of the bulb, the user will be able to purify over 2,000 gallons of clean drinking water.



One fully charged unit will purify clean drinking water within 48 secs (.5 liter) or 90 secs (1 liter)

No odors or chemicals involved

Solid construction

Water resistant

Easy to operate, requiring very little skill. Being a typical guy, it is in my male DNA that I shall not read any manuals that come with a new piece of gear, and I did just that. Upon receiving the Ultra, I took it out of the box, charged it, and started my testing. Due to the helpful bright obvious symbols on the screen, I suspect someone who doesn’t even speak English could operate the device. Later on, I eventually did read the manual and found it well written for the average user.

The tapered shape of the Ultra fits snugly into my water bottle (repurposed Gatorade bottle) allowing the probe to reach the water, and the screen/button outside of the bottle allowing for easy access.

Unlike the ceramic and membrane filters, the Steripen will continue to work in freezing conditions.  With temperatures below freezing (32 degrees F), I buried the Ultra in a snow drift and left it overnight to simulate a lost SteriPEN on the ground in the winter. In the morning I dug it out of the snow, powered it on, and treated a liter of water. The unit did add extra time to compensate for the cold water and operating temperature. This is noted in the manual that this may occur under these conditions.


  • Another factor for those in cold climates is treating pure snow. Pure snow melt may require some salt or electrolytes added to the water (to increase conductivity) allowing the unit to turn on. Once again I put the Ultra to the test. Snow was melted using my MSR Pocket Rocket and poured into a Gatorade bottle. The Ultra activated without any problems. Considering I live in the “Tail Pipe” of the northeast, it didn’t surprise me that there was plenty of the extra “good stuff”, i.e. pollution and/or particulates in the snow to allow conductivity. Other locations and snow quality may differ.



  • Electronic device requiring battery recharge
  • Can only purify 1 Liter at a time
  • Must use wide mouth bottles (i.e. Gatorade bottle) that will fit the probe

Personal Use:

Over the course of a month, I treated 164 liters of water for my own personal drinking use.

During that time, the Ultra purified my water with no issues. I did manage to pull the protetive rubber USB charging cover when removing the charging cable on my second charging. I fixed the cover shown below using a paperclip. A dab of super glue may solve that minor problem.

I also found the plastic probe cover difficult to take on and off. A little less friction would be ideal.

Cost ratio per liter compared to other water treatment methods:

Aquaramira Drops = .13 cents/Liter

SteriPEN= .01cents /Liter

Customer Service & Warranty?

I contacted SteriPEN as a “customer” and asked about bulb and battery replacement. According to their helpful customer representative, the following are the costs for various replacement items:

New Battery $10

New Bulb $20

Any warranty work is a $7.00 return shipping fee


In summary, I would recommend the SteriPEN Ultra to anyone looking for a water purifier that is simple to use, especially those in colder climates. I would also recommend using a pre-filter to reduce particulates in the water and to maximize the effectiveness of the SteriPEN Ultra.


Feedback received about the review:

“Thanks for the very thorough review of the SteriPEN Ultra! We really appreciate the time you put into this … and are so happy to see that your results on the number of treatments per charge exceeded our projections!”