Review: MSR Water Filters

The best way to get water while camping? You filter it straight from the source!

One of the most common questions I see regarding backpacking is what you do about water. I get asked if I carry all of my water for a multi-day backpacking trip. The answer is no!

Unless you’re hiking or backpacking through a desert environment like on the Pacific Crest Trail through the Mojave Desert in California, then yes, you have to bring all of the water you will need for the duration of the trip. Most of my adventures are in the mountains, and I make sure there are plenty of places to fill up on water along the way. Even on a day hike, I bring my water filter so if I run out of water, I can filter some more.

Before we dive into the MSR water filter review, there are a couple of things you need to know.


Our immune systems are not adapted to drink “dirty” water. The water that we get at home has been filtered and treated before it even comes out of our facet. Because of this, we aren’t adapted to combat waterborne diseases.

“Dirty” water doesn’t mean it just looks dirty. That’s part of it. But “dirty” water also includes water with natural organic matter (humic and tannins), organic chemicals, sediment, microorganisms, and inorganic chemicals. The water looks clean because it’s runoff from melting snow in the High Country, but that doesn’t make it clean.

Waterborne diseases such as Giardia and E-Coli are commonly found in our natural water sources. In some areas, it might be safe to drink straight from the source, but it’s always better to filter your water just in case and avoid getting sick.

Treating your water is like wearing a seat belt. It’s a minor action that you do to prevent and prepare for the worst-case scenario. Not all water you’ll find in the backcountry is dirty but better safe than sorry right?


These aren’t the average water filters that you’ll find at your local Target. Something like a Brita filter is great for at-home use, but in the backcountry, it won’t filter out waterborne diseases like Giardia.

I’ve used these water filters to drink out of dirty ponds right on the trail when I’ve gotten desperate and have been fine. By desperate I mean I ran out of water and I was at least a mile from the nearest water source (a river or a lake), and I needed water.

So let’s dive into my review of MSR’s two most popular water filters.

f you’re new to backcountry hiking and backpacking, this is a great filter to start with! It packs up small and you don’t need to stick your hands in the cold water.

It’s great not to have to dip your hands in the cold stream when you’re trying to filter water before bed, or even when waking up in the middle of the night, short on water.

One end goes into the water source, the other end you squeeze to filter water into your water bottle or bladder. This is a great filter for shallow water or awkward to reach sources.

It surprisingly worked quickly. I was expecting for such a small filter, that it would take a while to fill up my bottle, but it worked fast. I didn’t time it, but according to MSR’s website, it filters one liter in about 60 seconds. It also didn’t tire my hand out. I’m sure if you had to filter water for your entire group, your hand will start cramping, but for one person, my hand was fine!

The TrailShot only weighs 5 ounces and can filter about 2000 liters.

It’s safe for backcountry use and effectively protects you from most of the harmful microorganisms found in the US and Canada, including bacteria, protozoa, and particulates. It does not protect you from viruses, so it will not be a good choice for filtering water in developing countries. To help protect you from viruses, use MSR’s Aquatabs in addition to using a filter.

I was excited to try this filter because of the hand crank. It was my first one and did not disappoint! Especially if you have a Nalgene bottle, more on that further down.

The MiniWorks Ex filter is bigger than the TrailShot and the biggest filter I’ve used so far. In addition to filtering out bacteria and protozoa, it also removes chemicals and pesticides.

This filter won’t remove viruses if you’re looking for a filter that will remove viruses, take a look at the MSR Guardian™ Purifier filter. The Guardian filter meets testing standards used by the U.S. military, for the removal of viruses, bacteria, protozoa, and sediment from “worst-case” water conditions. To help protect you from viruses, use MSR’s Aquatabs in addition to using a filter. The carbon core filter also removes unpleasant tastes and odors.

This filter weighs 1 pound and treats 2000 liters. It’s not the lightest backcountry filter, but it’s effective, easy to use and very reliable. It also does require more force to pump than the TrailShot.

Similar to the TrailShot filter, you put one end into the water source, and the other end you use to filter water into your bottle. Going back to the Nalgene bottle, the end where the clean water comes out of securely twists onto the mouth of a Nalgene bottle. So if you’re worried about spilling, here’s a secure way to filter your water.

The hose on the MiniWorks Ex filter is longer making it more optimal for harder to reach water sources and again you don’t need to stick your hands in the freezing water. You can also sit in a more comfortable position while filtering! So if you have a group to filter for, here’s a bonus. The hose also comes with a pre-filter and afloat at the end of the hose. The pre-filter is designed to remove debris and guppies from the water before it reaches the main filter. The float keeps the hose from going too far down and picking up more debris. It can easily be removed and repositioned if needed.

The filter also comes with a cap that goes on the part of the filter where the clean water comes out of. Keep this cap clean! It helps protect the clean part of the filter that goes on your water bottle from being cross-contaminated. When you’re not using the filter, put the cap on and don’t lose it. Most likely the hose will still be wet when you’re done so this helps. I usually store my wet filters on the outside of my pack to prevent getting everything inside wet, including my down sleeping bag and jacket. Those are two things you don’t want to get wet.

When you get home, clean your filter. MSR recommends removing the ceramic filter (the main filter) and scrubbing it with a clean sponge and tap water. Use the red part on the filter’s cap to measure the ceramic filter and see when it’s time for a change. If the red part fits around the filter, it’s time for a new one. But don’t force it, it can damage the filter. For more from MSR on how to care for this filter, click here.

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