Filter or Purifier, You Decide: Katadyn Explorer Pro Review

The spring runoff gurgles downstream, as I settle in next to the river flowing listlessly by. Thanks to the recent warm temperatures, snow hundreds of miles away is melting and catching everything in its path as it flows down towards the ocean. The runoff river may look drinkable at first glance, but it still needs to be filtered. Luckily, I brought my Katadyn Explorer Pro water filter.

I pump the water through the filter and into my water bottle. It looks crystal clear, and I take a big swig of the ice-cold filtered water that tastes as good as anything I’ve ever had from a tap — better, even.

This is part of a new filter series from Katadyn specifically for backcountry and expedition trips. The Explorer series combines ceramic filtration, activated carbon, and virus removal in a modular portable system engineered for reliability in the field. It’s one of the safer options for clean water in the most dire environments, and the full Explorer Pro kit comes at a premium price

In short: The Katadyn Explorer Pro ($450) is a premium pump filter and purifier that uses a unique three-stage system. The first stage is the microfilter, which removes bacteria, protozoa, and particulates. The second stage is an activated carbon filter to improve taste, and the third stage is an optional virus-removal stage. Whether you’re filtering water from natural sources in the U.S. or purifying it from questionable sources abroad, this filter will keep your water clean and tasting fresh.

Check out GearJunkie’s guide to the Best Backpacking Water Filters.

Katadyn Explorer Pro Review

My trail name is Fish, in part because I drink so much water while backpacking, and I also happen to love fishing, so I filter a lot of it.

Without clean water, you aren’t going to get very far, which is why I take water purifiers and filters seriously. If you buy a bad pair of shoes or a tent, it’s not going to make you sick, but a bad filter can mess up more than just a hike. 

In my time hiking and trekking around the globe, I’ve tried every kind of filter, from UV filters to pump filters, gravity filters to squeeze-hollow-fiber filters. I’ve used tablets and boiled water and, at times, drunk straight from the source.

I’ve filtered out of cow troughs and mud holes, where you have to really trust your filter. The good news is the Katadyn Explorer Pro is a water purifier you can rely on in any condition or environment — even abroad, where waterborne viruses can be a threat. It was designed to raise the bar for expedition-grade filter and purifier systems.

I put it to the test during spring runoff in Colorado’s Poudre River. It certainly wasn’t the dirtiest water in the world, but nevertheless full of particulates and debris. The Explorer Pro did not disappoint.

On the Trail

The pump-action purifier is easy to assemble and use. Simply put the filter end of the hose into the water and the other end into the clean water bottle. The bottom of the Explorer Microfilter is threaded to fit onto wide-mouth Nalgene bottles (as seen above). Then start pumping.

The pump is easy to press with a smooth action. It pushes the dirty water through a ceramic filter (stage 1) to remove particulates and microplastics. Then it passes through an activated carbon filter (stage 2) to remove bacteria and improve taste. Finally, it passes through the removable “Pro” hollow-fiber membrane, which eliminates viruses. This attachment twists onto the bottom of the Explorer filter. (More about this attachment in the next section.)

Both the Explorer Microfilter ($200) and the Pro attachment ($250) can be purchased separately, or together ($450). The microfilter weighs 1 pound, 1 ounce on its own, and the Pro attachment adds 1.76 ounces (for a total weight of 1 pound, 2.76 ounces).

From the outtake hose, clean water trickled into my water bottle easily. Katadyn claims a flow rate of 1 L per minute. In reality, it took me 2.5 minutes to fill my 48-ounce Nalgene — slower than claimed, but still fast enough.

Since I filtered straight from the source, I didn’t need to stress about using a dirty water bottle to collect water, as is required by some other filters. I found the pump action to be quicker and easier than a squeeze filter. It’s not as quick or easy as a UV filter, where all I have to do is click a button. However, the Explorer Pro’s ceramic filter, combined with the hollow-fiber filter, also removes particles from the water, which UV filters don’t.

With the ‘Pro’ Attachment

When you add the Explorer Microfilter’s “Pro” attachment, it gets a little more complicated. Since it threads onto where the Nalgene would go, you have to clip a second tube onto the bottle for the clean water. This took me 3 minutes to fill the same 48-ounce bottle. Doing it on your own can be a bit tricky.

You need a flat surface to set the bottle. Alternatively, you can also hold it while pumping; it just requires a third arm. Because the water bottle is open while you’re filtering, make sure not to drip dirty water into it.

One nice thing about this water filter is that it improves the taste of the water. The water I filtered was clear and clean-tasting. Some filters don’t use activated carbon and can leave the water tasting funky.

The Explorer Pro comes with a convenient carry bag and weighs just over a pound. If you don’t mind that kind of weight, it’s easy to pack and throw into a backpack.

Made With a Modular Platform

What really sets the new Explorer series apart from other pump-action filters and purifiers is the modular platform. This feature offers two configurations using a single filter.

The Microfilter by itself uses only the ceramic filter with activated carbon to remove bacteria, protozoa, and particulates. It also helps improve taste and reduces chlorine and odors. Attaching the Explorer Pro module to the bottom adds a hollow-fiber membrane filter designed for virus removal. With the Pro attachment, it’s a complete three-stage purification system. 

The Pro setup is important for trips where water may contain viruses. In other parts of the world, microfilters alone aren’t enough to protect you from waterborne viruses. Having a virus-removing purifier you can attach when you need it, and remove when you don’t, is useful.

Room for Improvement

There are some drawbacks to using a pump filter. The included intake hose is not that long. That makes it hard to keep the filter in a flowing stream without it drifting back to shore. You have to hold the filter out over the flowing water. Alternatively, I looped it around a rock to get it to stay in the deeper water.

The addition of the Explorer Pro also adds the challenge of trying to filter and balance the open water bottle. If you have someone to hold the bottle for you, it’s no problem. However, that tube is also short, and the bottle can easily fall over or get contaminated since it is open.

Finally, weighing just over a pound, the Explorer Pro is not the best option for ultralight thruhikers. If you are looking for a lightweight option, check out our guide to the Best Backpacking Water Filters.

Katadyn Explorer Pro: Who It Is For

In the decades I’ve been backpacking, I’ve encountered some of the worst water imaginable. I’ve boiled my water to ensure it is safe while backpacking along the Texas–Mexico border. I’ve purified it from streams in remote regions of India filled with leeches and who knows what else. On a couple of occasions, I’ve drunk crystal-clear water straight from high-alpine streams where you can see the source (still not recommended).

Sometimes filters suffice for my needs, sometimes purifiers are needed. It’s nice to have the option of switching between the two. The Explorer Pro does that. This filter was built for expeditions where water contamination can be dangerous and even deadly, but it also works as a regular microfilter.

With the Pro attachment, it is more robust than many filters on the market. If you travel to areas where there may be human or animal waste in the water source, but also backpack in areas where a microfilter would suffice, this filter offers both levels of protection. It’s a very versatile tool.