MSR MiniWorks EX Water Filter for the Boundary Waters and beyond
by Red Rock Wilderness Store

There are a lot of water filters out there for camping. We have sold and tried many of them with less than consistently great results. In fact, some of them were just downright consistently troublesome. Without mentioning several brand names that are absolutely sub-par in my opinion, I CAN tell you who makes the best water filter you can buy. It's not the most expensive, nor is it the most complicated yet it works very consistently and most importantly, it is field serviceable. You can watch all the parts function with relative ease, no tools required. Prior to the MSR MiniWorks EX water filter, those other water filter systems required that you to clean them with a little round brush when they get dirty and cloged. These types are still being made and for some folks they apparently work fine, but for the life of me, I could not see why anybody would design equipment that consists of an inaccessisible ceramic filter that you have to stuff a brush up into to clean. The hole you need to visually inspect to clean with the provided brush is dark in every case. You can't see doo-diddly towards the back of the filter. The dirt you are trying to clean is also dark. So when your filter is clogged (very hard to pump), you need to shove a brush into a dark hole scrubbing back and forth to try to dislodge the trapped dirt which is hard to discern from darkness. That's the first problem.

The second problem with the "scrubbing hole" type filters is that the smaller the size of particulates being filtered out (.3 microns), the more pressure needed to drive the water through the ceramic separating the bad parts out of the good water. This requires a lot of pressure that can build up in the pump. It's basically low volume - high pressure being employed and the pressure gets even higher when the filter gets clogged and it's not at all unusual to literally blow the top of the unit, cracking the plastic beyond repair. Now, I saw this happen to two different brands several times. We stopped selling them. I wouldn't give you two cents for one. Both companies who made the filters replaced the parts cheerfully which is great. What wasn't so great was that some of the clients using the blown filters were 3 days into a 5 day wilderness trip or some derivation thereof. Last I checked, the greatest customer service staff in the world still won't paddle out to your camp to give you the part you need. Crank up the fire, you're gonna be boiling water for the next three days.

That bring us to the ONLY water filter I've found that makes total sense. The MSR Mini Water Works or the MSR Water Works. Click on the pictures below to see the larger image.

This is the MSR Mini Works EX filter assembled and ready to go.
This is what it looks like when not wound up by the suction hose. The round cap screws into the bottom of the pump housing. It also holds the caliper.
MSR Mini Works EX broken down. Pump and handle (red) filter housing(grey tubular thing) ceramic filter(beige middle, black top, black bottom with orange O ring on bottom), red caliper, bottom cap.
Ceramic filter (MSR EX) slides in here with the rubber O ring on the bottom going in first.
This is why this filter is particularly cool. You not only can feel when the filter is clogged and needs cleaning, you can actually see that it's dirty through the pump housing. I don't know of any other pump that allows visual examination without taking it apart or looking up a little dark hole.
Here's the scrubby pad, provided by MSR. It appears to be a simple scrubby pad you can by at a grocery store.
When pumping water slows down and/or it gets really hard to pump water, your filter is dirty. Use this scrubby pad to scrub of the dirty layer of ceramic.
After you've scrubbed the pad a bunch of times, take the caliper that is attached to the bottom cover and try to slide it over the ceramic. If the caliper slides over the ceramic, it's time to buy a new filter.
Here's another reason to like this filter. All the parts can be taken apart by with no other tools. A little bit of MacGuyvering and one can fix a part if necessary. We once had a customer who lost the pin (see far left arrow) while on a canoe trip. He whittled a stick and replaced that pin. Pump worked fine right to the end of his canoe trip
There are two ways to container the water. You can screw most bottles to the bottom of the filter housing to prevent cross contamination. This is handy and frees up having to hold or juggle a second container. It's not a huge requirement to connect a water bottle to the filter (unless you are in Mexico City during an earthquake) especially when you have containers that don't fit the filter. So simply cut 10" or so from the intake hose and attach it to the outlet connection you find in the bottom. Then you can fill a bottle with any size neck. This method does not seal against cross contamination so be sure to keep your water fights to a minimum at the time of filtering.

Joe's Water Filtering Tip: Immediately upon arriving at your new campsite, take a large pot from your cook-kit (or other sizeable container) and fill it up with water from the lake. Set the bucket on a rock and go set up your tent, tarp, Thermarests, and the rest of your camp. When you are done (at least 15 minutes later or longer), come back to the pot with your water filter and keeping the intake at least an inch off the bottom of the bucket so as not to disturb the water. Pump your drinking water into your clean drinking containers. Note that on the bottom of the bucket with the unfiltered water, you will see a fine fuzz laying down there. These are the solids that precipitated out of the undisturbed water and you will NOT be sucking them up into your filter. This results in a filter that lasts significantly longer than those which are used to pump directly from the lake. Less crud, less cleaning, faster pumping. Also, if you are pumping from a bucket on land as opposed to over the side of the canoe, if you become a butterfingers, you won't see your whole water filter system going to the bottom of the lake. I don't know if they float and I don't care.

The MSR EX filter cartdge will pump up 2,000 liters of water depending on conditions. If you do the "bucket precip" thing in my tip above, this water filter should last you for a long, long time. It removes particles down to .3 microns (that's "point" three which is much less than one) which is ridiculously small. Giardia Lamblia (sponsor of beaver feaver/Montezuma's revenge in a bad way) are about 5 to 7 microns in size. This pump is a bit on the overkill side, but if they can do it, why not?

One precaution: When handling the filter itself, do not drop it because being ceramic, it can crack. If it cracks, you need a new one.

So, choose your filter pumps wisely for going out on a wilderness canoe trip adventure. Go ahead and research all the other available brands. MSR Mini Works EX and the MSR Waterworks EX (same filter cartridge used but also has a pre-filter section with charcoal and other goodies) will do a good job for usually a very long time. There may be something else out there like this MSR pump, but I'm not aware of it. When I find equipment that works very reliably, I don't look too hard for something better. No need for our wilderness camping application. -JB-

Order an MSR Mini Works filter pump here


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