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Reviews > Water Treatment > Filters > MSR SweetWater Filtration System > Owner Review by Valentin Romanov

MSR SweetWater Filtration System

Owner Review by Valentin Romanov
October 28, 2013


Product information

MSR SweetWater Filter

Photo courtesy of MSR

The Specs:
  • Manufactured by Mountain Safety Research (MSR)
  • Manufactured in 2011
  • Website:
  • Filter: Silica Depth
  • Filter pore size: 0.2 microns (0.00008 in)
  • Filtration rate: 1 liter per min
  • Listed Weight: 11 oz / 320 g
  • Measured Weight: 12 oz / 340 g
  • Dimensions (width and length): 2.5 in by 7.5 in (5 cm by 19 cm)
  • Measured dimensions As listed
  • Filter life span, listed: Around 750L (198 US Gallons)
  • $99 US
Features obtained from manufacturers website



The MSR Sweetwater filter comes in a nice, perforated bag. The entire mechanism fits snugly into the bag where by the entrance is closed off using a pinching mechanism. The bag is robust meaning that it will not tear after continual removal from the backpack.

This product will be evaluated from the point where the pre-filter is inserted into the water source to the out-take hose leading into the bottle.

The pre-filter is a small, circular 3 mm (0.12 in) thick device to which the intake hose is attached. The pre-filter is the point of contact with the water source. The housing is designed using ABS (Acrylonitrile Butadiene Styrene), used for is high impact resistance, chemical resistance and toughness. ABS is shatter resistant between temperatures from -20 to 80 C (-4 F to 176 F). To note: ABS is flammable when exposed to extreme temperatures such as wood fire and will eventually burst into flames if left in contact with the flames [1]. ABS can also be damaged by sunlight, as such the filter should not be left out in the sun for extended periods of time.

The mesh found on the top of the housing is designed using stainless steel, criss-crossed to prevent particulates of 75 micro-meters (0.00295 in) or greater from entering the filter. As such, the pre-filter ensures that distinctly heavy particulates do not enter and prematurely block the filter. To ensure that the nozzle does not sink to the bottom of the stream or get caught in between rocks, a floating device is attached half way down the tube. The flotation device ensures that the water is pulled from the greater body of water rather than the sediment bed.

From there the water travels through an 81 cm (32 in) long tube to the inlet of the filter. The cable is made from silicon with an inner diameter of 3/16" (0.476 cm). Silicon is a durable, chemically inert material with a high melting point. As such, the tubing is hard to damage and so should in theory withstand quite a lot of abuse.

The hose is attached to the filter cartridge which is essentially a hollowed out chamber with an inlet and an outlet port. The chamber is made out of PC (polycarbonate), a thermoplastic used for its high impact resistance and overall durability. This filter uses activated carbon for adsorbing molecules within the porous structure helping to eliminate any odors in the water. In addition, the silica depth filtration technique employs a filter size of 0.2 um (0.00008 in). By this process, the manufacturer states that the filter is able to eliminate over 99.99% of all waterborne bacteria and some parasites such as Giardia and Cryptosporidium. Furthermore, filter life is estimated at around 750 L of water at 1 L per minute. If the filtration rate dramatically reduces it may mean that the silica filter is getting blocked. In this case it may be cleaned using provided filter brush.

The water is pumped into the filter via a cartridge affixed to a handle. The pump handle is attached to the housing via a retainer pin which slots into a hole allowing for lever like motion of the handle. Built into the housing is a pressure release valve ensuring that if any clogging were to occur water would come pouring out rather than cracking the filter. The pumping mechanism is screwed clockwise onto the filter. The lever-action is designed to provide a 4 to 1 mechanical advantage, both on the up and down stroke.

The purified water is then delivered into the bottle via another 81 cm (32 in) silicon tube. To ensure that the hose does not slip out of the bottle, a universal bottle adapter is attached to the end of the hose.

In the field

This filter was purchased for our backpacking trip to South America. It lasted 8 months however we noticed a drastic reduction in performance after 6 months. The filter was used to purify water for 2 people. Locations of usage included national parks in Colombia, Ecuador, Peru, Bolivia, Argentina and Chile. As an average I would estimate that the filter was used to purify 4 L of water, 4 days a week. As such, using this rough estimate, the filtration system purified around 550 L of water over a period of about 140 days.

The filter was used in the following conditions: Clean, mountain fed streams, glacial lakes, fresh water lakes, dirty, run off streams and hostel sinks.

It has been used in a number of environments from the heat of the Colombian jungles 35 C (95 F) with 100% humidity to the frozen, glacial mountains of southern Chile 0 C (32 F).


The MSR Sweetwater filtration system performed as expected. We found that it was very easy to set up and to pack up. The pump handle comes apart via the removal of the retainer pin. The handle comes flush to the body of the filter and is then secured to the body via the wrapping of the silicon tubing. We had no problems with assembly and disassembly of this unit.

I really enjoy the fact that the pre-filter can be lowered into a body of water. This means that I don't have to bend over a rock or go wading into water in order to scoop up an appropriate amount of water for filtering. The pre-filter works like a charm and in a running source of water, does not block at all. The only issue with blockage is when the filtration system becomes blocked. Initially the hand unit can filter about a liter of water per minute however after 6 months of use the rate had slowed to about half that. Luckily, the setup comes with a filter brush. In order to remove the build of sediment within the filter, the filter brush needs to be inserted into the tube and gently twisted. While this gets rid of most of the build up, it is a short-term solution. The filter will need to be replaced. We used the filter for 2 more months afterwards and noticed that because of the reduced performance of the filtering system, the filtration rate continued to reduce to a point where every other stroke water would come squirting out of the pressure valve. The device is still usable at this point, however it becomes a pain to apply enough leverage for effective water filtering. We could rarely find the appropriate parts in South America, and even if we did, the price was usually double the recommended retail price.

Furthermore, the filter performed well in sandy conditions. With use, I noticed that sand tended to build up around the point of where water entered and exited the filtering system. In order to properly clean the system, I had to disassemble all of the tubing. Beyond that, this filter requires little maintenance and is quite robust.

Overall, I really like this filtration system. It packs very well, with no loose hinges or other bits that may snag on the inside of the bag. I found that it is quite easy to use when on a trail or even in a hostel. The life span of the filter itself will be determined by the level of sediment in the water. I was quite impressed with how long our filter lasted considering that we filtered in every imaginable water environment.


My reasons for why I would buy another one

The good
  • Packs well
  • Light
  • Fast filtering rate
  • Convenient to use

My reasons for holding back

Could be better
  • Additional filters are expensive

Read more reviews of MSR gear
Read more gear reviews by Valentin Romanov

Reviews > Water Treatment > Filters > MSR SweetWater Filtration System > Owner Review by Valentin Romanov

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