The more testing I do with Ziplock-style bags, the less enamored of them I am becoming. It seems that the original sample I was testing was very good, but that level of quality hasn't been consistent across other samples I have tested. The problem I am seeing is some very slight leakage from the zipper, which could result in significant water loss over time. <br><br>The leaky zipper problem seems to affect the pleated designs I tried of both the Ziplock brand and the Glad brand. Because these bags stand-up, it is less of a problem, but still not good. Of the flat-style bags, the Glad brand seems to be of better quality, but testing shows that some of them do leak anyway. I still like the idea of a zipper bag as a compact water storage option, but I will be testing any bag that I intend to pack before I add it to my gear.