I’m also pretty baffled, to be honest. The deterioration is all right around the edge. They were stored in an interior ground floor closet that stays pretty cool and is dark except when someone turns the light on to get the vacuum, so…not that often 🙂  The differences definitely seem to be between the stacked vs not stacked containers so lesson learned there!
Thanks! I never touch the inside of the containers or the lids after I bleach them to minimize contamination opportunities. I previously air dried after using the concentrated bleach. This past year was the first year I’ve had issues and while I do think it’s from putting too much weight on them and the lid gaskets starting to deteriorate, I did a rinse and then filled with tap water right away. I am now more than ever a big fan of adding a bit of bleach in, as you can think you have been careful and still open it up to an unpleasant surprise! Fresh bleach is a bit of extra insurance. Â I also won’t be stacking my water stores any more!
I might pick up some of those. In opening up all of my stored water, the water in the Waterbricks that were stacked all had visible issues and the ones that weren’t stacked look fine. I did notice that all the lids were showing signs of deterioration inside after 4 years of use. I’m replacing all the suspect WaterBricks with Scepter containers.