Yeah, it didn't take long for my sawyer bag to start leaking. The same with my friends. If you look online, everyone is complaining about this. This isn't a quality control problem, it is an inherent design problem. Either the plastics don't match, or the heat sealer has a bad part. At any rate, the local outdoor store had a box of Eddie Bauer 1.5 liter bags with the same thread size for $1.50 each. I bought more than 10. Then I wrote "dirty" on one. Hasn't failed yet, despite my abuse.

My last trip, I had to filter from a lake. I found that if I use another container to scoop water from the lake (I used my MSR collapsible canteen, wide mouth), then poor it into my "dirty" bag, then it is easy. That means another container that is dirty, but it comes in handy with putting out fires because you don't want to filter that water. And, you can still use it to carry water, you just have to filter it first. Plus, my dog carries it empty in her bag.