I also use Fold-A-Carrier water jugs but for a completely different purpose.

When I am the lone person in aluminum boat with a tiller outboard the nose of the boat is often to to high to allow proper trimming. So I put a full 5 gallon Fold-A-Carrier in the nose of the boat to even out the weight. This is easier than (and not as hard on the boat) putting rocks in the nose and if I carry over to another lake, I just dump out the water and portage the empty jug to fill at the next lake where I have a cached boat.

Fold-A-Carriers are not very tough, but if the leak is in the top, with a sharp knife they can be converted into a folding wash basin.

Mike