Let me throw in my 2c worth...I too use the Aqua tainer from wal mart. I have tree of them and I do stack them in the garage. I use them for holding "wash water" at the sink. It has a valve that can be left in the open position that allows you to wash and rinse things without having to hold open the valve. Granted you wouldn't want to leave it open and allow too much to go down the drain during an emergency but it is handy for the kids to wash from. Not using it for 'potable' water also means I don't have to rinse EVERY last drop of the soap out when I clean them. We have at least 10 cases of bottled water that we use for consumption and also a reverse osmocic H2O system so we only relly needed stuff for the hurricanes for 'cleaning' water' anyway.

We love the containers. They stack well and are well balanced. They do not roll off the counter like the soft sided collapsable containers. They are a little heavy but they are much easier than larger containers and can be handled by all in the family.