A Technique for Using a Steripen with a Hydration System

By Will Rietveld

My (current) favorite lightweight water purification system is the rechargeable Steripen Freedom, a 2.65 ounce (without carry case) device that purifies water with UV light. Why? – Because there is no wait time or sucking through a filter, just treat and drink.

I prefer to use a lightweight hydration system carried in a side pocket, but the flask has a narrow opening, which is not amenable to using a Steripen. The Steripen requires an open container or wide mouth bottle to wave the device around in the water.

So how do you use it with a hydration system, in ultralight style, which means minimal extra weight?

My ultralight backpacking friend Tom Galbraith came up with a clever and simple solution, described below. Here’s a photo of Tom on a recent backpacking trip two weeks after he bicycled 1700 miles on the Continental Divide road route. Credit for the idea goes to Tom, and I show the method here with his permission.

The technique is to use a gallon size zip-lock bag to scoop up water, treat the water in the bag with the Steripen, then transfer the water into your hydration reservoir. We like to use a Platypus flask.

Equipment needed is a Steripen, 1-gallon zip-lock plastic bag with slider closure, and a flask.

Scoop up water into the plastic bag. It’s easy to do while holding the bag open with two hands. I often treat 2 to 3 liters at a time and share the treated water with my hiking companions. For mountain hiking, I usually carry 1 liter or less to minimize weight.

 

Treat the water with the Steripen, which uses UV-C light to sterilize organisms. The Steripen Freedom uses a 48 second cycle to treat 1 pint of water, so multiple cycles are required, depending on the quantity of water. Simply dunk the Steripen into the water (it turns on automatically) and wave it around in the bag.

Transfer the treated water into the flask. If you are doing it alone, it helps to open the slider on the zip-lock about 1.5 inches, lay the zip-lock bag over your leg to support it, and pour into your flask held with the other hand.

This technique is a head-slapper in its simplicity and adds only a fraction of an ounce to your pack, besides the Steripen.

I have tried just about every water treatment and hydration system available, and this system is my current favorite. Its not the lightest -- Aqua-Mira drops or tablets are lighter -- but I like the convenience of fast treatment with the Steripen and being able to drink on the fly with the hydration system. In the mountains, where water is abundant, I treat and carry a liter of water at a time, which is a good balance of light weight and convenience.