Platypus GravityWorks™ 4L Filter System

This is the easiest and quickest water filtration system I've used. Four of us biked to Goldmyer Hotsprings for a few days and this kept all of our water bottles filled and cooking was a breeze with this easy system of using gravity.

Fill it and forget it! Great water treatment option for any basecamp.

We've had our 4L GravityWorks system for seven years now (still on the original filter!) and will never consider going back to a pump system. Our typical use is in the Boundary Waters and Ontario's Quetico Provincial Park on 10-day trips. On our last portage before our destination lake for the night we pull the dirty water reservoir out of the storage bag, paddle to the middle of the lake, scoop up four liters of water, then head for a campsite. Before setting up the tent, we hang the gravity filter and we have clean water before gear is in the tent! With proper backflushes, air purges, and cleaning/drying before storage, slow filtration has never been an issue. Only one problem: the black 'cleanside cap' disappeared on our recent Quetico trip. Where do I get a replacement? And shouldn't it be a brighter color?

I bought this 6 years ago for an annual canoe trip in Northern Ontario. It works great year after year, I always backflush it before putting it away and have never had any issues. During use it will need to be backflushed every 30 - 40 liters when I notice the flow is slowing down. At this point I've probably ran around 300 liters through it and it still works like the first day.

Spent 10 days in the backcountry elk hunting and this worked amazing!

I have used both the 4L and 6L for hiking groups with scouts in tropical Australia over the last 5 years. I went from the 4L to the 6L only because I accidently lost the 4L! :-( It has high usage with up to 10 people using it over 2-4 day hikes, 2-4 times a year. I follow the long term storage instructions and the filter cartridge has tested fine prior to use in the following season. Without detracting from the 5 star rating, my two gripes are this: 1. there should be another flow clamp on the dirty side of the filter for those occasions where 6L has been filtered but more water has been added to the dirty bag - this would allow flow to the filter to be stopped when the clean hose needs to be disconnected for use. As it seems the clamp cannot be purchased by itself (only part of a hose replacement kit), I have used a plastic clothes peg to crimp off the line as a solution. 2. the zip-lock on the top of the dirty bag can be incredibly hard to squeeze shut and it is even more difficult for youth who are trying to do it. Sometimes if it isn't quite done, when the bag is picked up, it will pop open. A fold over system with a slider to seal the top as can be found on 'Osprey' water bladders, or the top of a dry bag would be a far easier design option to use in the field. Overall, an amazing, functional system.

I have had the 4L gravity system for 5 years now and just upgraded to the 6L system. I love this system. I do carry a backup filter and have had to use on one occasion due to my filter being clogged because I did not backflush at all for a couple of trips. I did backflush at a later date at home and this original filter was back up and going good. The original 4L dirty bag is coming apart at the top now but I have use so many times I feel that I have gotten more than my money’s worth. I have put this thing through the ringer for years. I do clean per the instructions included before storing. Another great thing about this system is you can carry water in the clean reservoir with a simple plastic bottle cap. I have done this several times on top of my pack when on ridge’s requiring water to be packed in. I have tried some other methods and this is the best I have found. We typically hike 40-80 miles a year and this has been a wonderful asset out there. Happy Hiking

This is the first gravity filter system I've owned. I owned pump filters in the past. This purchase was long overdue as it is a tremendous time saver. I've used other people's gravity filters such as Katadyn. I chose this system over Katadyn because of the in line filter. I could use it to suck water out of cracks in rocks if needed which helps bridge the gap in functionality between pump and gravity filters. The only downsides I see to the inline filter over the in bag filter like Katadyn is that it is easier to clean and visually inspect for contamination/clogging with the Katadyn filters. This being an enclosed filter, it is harder to dry out. I often camp in below freezing conditions which can destroy a filter if water freezes in the filter. If and when this happens, I would get a Katadyn filter for winter camping and use the GravityWorks filter the rest of the time. I use alum powder for silty water and it keeps the filter running smoothly.