MSR Trail Base Water Filter Kit

By: Cory McLaughlin

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Just the Facts:

To meet the needs of multi-activity backcountry adventurers, we set out to engineer the most versatile water filter ever. The Trail Base microfilter kit features modular components that allow it to be used as a gravity system at camp, a pocket-sized filter on the trail, or a fast-and-light reservoir when you need to carry clean water with you. Whether you’re hiking, biking or basecamping, the Trail Base water filter kit offers incredible flexibility and options, making it the one filter that truly adapts to your adventure and the filtration task at hand.


Experience the Trail Base

 WARNING: Cancer and reproductive harm –


More info: Click here

Effective Against: Bacteria (99.9999%), protozoa (99.9%) and particulate. Hollow fiber filter meets U.S. EPA drinking water standards* and NSF protocol P231 testing standard.

Versatile: Modular components allow system to quickly and easily transform from a 2 or 4 L gravity system into a small trail filter and back.

Simple Transitions: Trail filter simply quick-connects into gravity system to create the complete gravity-fed filter system.

Complete Kit: Includes ultralight, durable clean water reservoir, which features our 3-in-1 cap for easy filling, drinking and pouring.

*U.S. EPA Guide Standard and Protocol for Testing Microbiological Purifiers


  2 LTR 4 LTR
Weight (Standard) 1 lb 1 lbs 2 oz
Weight (Metric) 0.62 kg 0.52 kg
Width (Standard) 6.5 in 8.5 in
Width (Metric) 12.7 cm 10 cm
Length (Standard) 15 in 15 in
Height (Standard) 3 in 2.5 in
Effective against bacteria Yes Yes
Effective against particulate Yes Yes
Effective against protozoa Yes Yes
Filter media Hollow Fiber Hollow Fiber
Filter pore size (microns) 0.2 0.2
Flow (L/min) 1 liters per min 1 liters per min
Flow (strokes per liter) 60 60
Cartridge life 1500 liters 1500 liters
Field cleanable Yes Yes
Field maintainable Yes Yes
Cartridge replacement indicator yes Yes
Material(s) Hollow Fiber PU
Country of Origin Made in the USA of US and Imported Materials Made in the USA of US and Imported Materials


My Story:

Water is one of the single most important items in all outdoor adventure. We base our adventures around water. Whether it is hiking along a stream or to an alpine lake or planning stops at a spring we always have to keep water at the forefront of our minds. Water is life and absolutely essential to survive. The problem us outdoorsy folks face is that not all water is created equal and while we must have it survive it must too be safe. Dirty water can actually make dehydration worse and ultimately could kill you. So how do we combat all the nasty little microbes that seek to infect us while also making sure to get the water we so desperately need? Well, that is where MSR comes into the picture. If you have ever been outside city limits the MSR brand should not be something foreign to you. They have long been aiding mountain goers by providing exceptional equipment for their adventures. The MSR Trail Base Water Filter Kit is just another fine example of a great company’s commitment to making quality gear for those that dare to adventure into the wilds.

I am a backpacker in the summer months and a hunter in the fall and winter. I have long maintained that hunting is often just a camouflage backpacking trip. We hike trails and mountains back into some of the most beautifully secluded areas and often only come out with a sore body and some great adventure memories. Because hiking/backpacking and hunting are so closely related the same gear works for both. In the fall of 2018 I had a great Idaho backcountry trip planned and a needed a new water filter to test out. Luckily I had worked out a testing sample with MSR and I was eager to hit the hills with this great system.

After running some water through the system at home and making sure that I familiarized myself with its details I was feeling very confident and ready to get into the woods. My plan was to camp 2 miles back from the road and hunt another 2 miles in from there. I needed to be light but I was not willing to sacrifice water as I am a huge believer in staying hydrated. My camp was also about half mile from my water source so I was very happy to have chosen the 4L version of the Trail Base as it would allow me to carry more water to camp with less need for extra trips.

I filled the dirty water pouch from a spring that was pouring out of the side of the mountain. The water here was clean and cool and while it was probably safe to drink right from the tap I was not willing to risk illness and ruin my hunt. I piece of bark helped me keep the bag away from the mud and made filling easy.

After filling the bag I stored it on a tree and went off to hunt for the night. Luck was on my side and I was able to harvest a nice bull elk that night. I was 4 miles from the road and I had a tremendous amount of work ahead of me. By the time I made it to camp I was completely out of water and exhausted. I passed out in record time and in the morning I was excited to filter the water I had collected the day before.

The water had been chilled by the night air and it was cool and delicious. I filtered the 4L or water that I had and began hiking out to the bull that I had waiting for me. I sopped again at the spring and filled the dirty water bag. I clipped it to the tree and left it to be retrieved on my next trip out. By the time I got back to the bag I only had about a half a liter of water left and I was more than happy to take a break and refill.

The next week of hunting was full of some really great adventure and some extremely long hikes. I filtered 32 liters of water on this trip and I was extremely happy with the results of this great filter. I loved its larger size as it made life convenient when I wanted to refill my water bladder and bottles in a one-stop-shop. I really loved the pre-filter that is in the bag as it makes sure to keep the main filter clear of nastiness. I also love that the filter and hose are not at the bottom of the bag so the real nasty stuff never gets into the line. To top it all off the in-line filter is yet another great stage of filtration before it enters the main pump filter. This insures that you get clean and clear water to enjoy!

The last thing I love about this filter system is that it can be broken down into a standalone filter for day trips. You can simply bring the filter and one section of the hose and use it like a pump to fill bottles or simply drink strait from the filter end. This system is truly an amazing addition to a backcountry adventurer’s kit. I really love what MSR has done here and would recommend this to anyone that asks. Fine job MSR, as usual!         

Find it Here:

What can be done better?

Nothing that I can see at this point but as always I will updated if anything changes. I do want to mention that this system is a bit slower than the Sawyer or Platypus systems I have used in the past. That said I think this is far better engineered and much more versatile than the others. 

  • Functionality
  • Value
  • Ergonomics
  • Durability