I have been using Sea-to-Summit silnylon drawstring bags to keep my down and clothes dry. When it starts raining, I also put on a Cuben pack cover. This has worked for me so far. I wouldn't want to dunk my pack into a river, though. I also don't know how the system would hold up if it would be raining continuously for several days. I tried the trash compactor bags, but they are simply too unwieldy. My sil bags have different colors, so I can easily see where the item is I'm looking for.