- No pumping: Just fill the dirty reservoir, hang it, and let gravity do the hard work.
- Fast: Filters up to 1.75 liters per minute; filter lifetime up to 1,500 liters of water.
- Effective: Meets all EPA & NSF guidelines for the removal of 99.9999% of bacteria and 99.9% of protozoa*.
- Ultralight & Compact: System weighs 10.75 oz. (305 g) and stows smaller than most 1L bottles.
- Group-ready: 8 liter (4.0L filtered + 4.0L dirty) total capacity easily supplies water for groups.
- Field-cleanable: Microfilter can be easily backflushed in 4 seconds to maintain filter performance.
- Hollow Fiber Advantage: Hundreds of tiny, hollow fibers, enable the microfilter to filter water faster than traditional filter media.
- Easy collecting & dispensing: Collecting water is easy—simply open the top, scoop water, and close; control delivery of filtered water with hose shutoff clamp.
Comes with: 4.0L Dirty reservoir, 4.0L Clean reservoir, Hollow Fiber microfilter, hoses, shutoff clamp, and storage sack.
*This includes Giardia, Cryptosporidium, E. coli, Salmonella and Cholera.
|Weight (Metric)||0.326 kg|
|Width (Standard)||3.25 in|
|Width (Metric)||8 cm|
|Length (Standard)||9.5 in|
|Length (Metric)||24 cm|
|Effective against bacteria||Yes|
|Effective against chemicals/toxins||No|
|Effective against particulate||Yes|
|Effective against protozoa||Yes|
|Effective against viruses||No|
|Filter media||Hollow Fiber|
|Filter pore size (microns)||0.2|
|Flow (L/min)||1.75 liters per min|
|Cartridge life||1500 liters|
|Water Bottle Adapter||No|
|Cartridge replacement indicator||No|
|Country of Origin||Made in U.S.A. of U.S. and Imported Materials|
Why is backflushing so important with the GravityWorks™ filter?
You must backflush regularly to maintain optimal performance of the filter cartridge. This is especially true in murky or very silty water. Since Hollow Fiber is not a depth-based media like ceramics, you don't clean by removing clogged material from the exterior of the filter media. Instead, you must rinse the particulate that collects on the outside of the Hollow Fiber membranes. Infrequent backflushing makes the particulate harder to remove and more difficult to restore the media’s flow capacity. Based on results from our in-house bio lab, we recommend backflushing anywhere from every 8 liters to after each use, depending on water quality. Our lab has found that the more you backflush the better your flow performance, and the longer life you can expect from your filter cartridge.
The easiest way we have found is to do it every time you fill your Clean reservoir. Just disconnect the hose from the Dirty reservoir and hold the Clean bag high for about 4 seconds. That’s all there is to it.
How does the GravityWorks™ filter do with tea-colored water?
This color of water typically comes from a high concentration of decaying vegetation adjacent to, or in, streams and lakes, resulting in a variety of organic acids. These include, but are not limited to, tannic, fulvic, and humic acids. These acids and the accompanying water conditions are very hard on ALL types of water filters.
Get your water elsewhere if you can. However, if no alternative exists and you are predominantly filtering these waters, we recommend using an MSR® MiniWorks® EX filter. Its ceramic element will collect all these impurities in its outer-most layer, allowing you to scrub away the clogged portion to restore normal flow rates. If you must use a GravityWorks™ filter, backflushing religiously and often will help to minimize the effect of these impurities. When you return home, add 2 drops of unscented household bleach to one liter of water and backflush this solution through the filter. This will help to break up organics that might be clogging the filter while also providing the recommended treatment of your system for long-term storage.
Limited use in these conditions will not have a dramatic effect, but extended use can permanently impair hollow fiber media.
What about freezing?
Once you have used your GravityWorks™ filter and wet the Hollow Fiber filter media, the fibers will still be wet. Therefore, it is important to prevent it from freezing, which can permanently damage the filter media. If you are traveling in areas where you are expecting freezing or near freezing temperatures, bring the filter into your tent, or even your sleeping bag. (Be sure to put the filter in a water tight bag to prevent leaks in your sleeping bag.) If you think your filter may have been damaged by freezing, perform a Filter Test before the next use.
For expedition-style travel where freezing temperatures are the norm, we recommend using the MSR® MiniWorks® filter. Its ceramic/carbon filtration media is better suited to such conditions.
What if the filter takes a hard drop?
We don’t recommend removing the protective bumpers (GravityWorks) or removing the Filter Cartridge from the protective housing (CleanStream). The bumpers on the GravityWorks™ filter are designed to protect the Filter Cartridge from most drops, but direct drops onto cement and any drops above 5 feet (1.5m) should be avoided. If the Filter Cartridge itself is ever dropped after being wetted and outside the protective housing, you should replace it. If you think your filter may have been damaged from a drop, perform a Filter Test before the next use.
Is there a way to filter into my reservoir without removing it from my pack?
Yes. Simply remove the bite valve on your hydration system and connect the end of the hose directly to your filtration system’s outflow port. Using a GravityWorks™ filter system, your reservoir can take the place of the supplied Clean reservoir, creating what is arguably the lightest, most compact and efficient way possible to get water. GravityWorks™ filters are available with direct-to-reservoir and direct-to-bottle adapters for optimum versatility.
Can I get small replacement parts for the Quick Disconnect fittings on my GravityWorks™ Dirty Reservoir?
Cascade Designs Service Center
For customers outside North America, please consult our International Distributor listings.