So this major water main break in the Boston area highlights the one drawback to a water storage arrangement like this--contamination. Which is not necessarily that big a deal if you're prepared beforehand. It's just another step that needs to be taken care of. Anyway, by the time the "boil order" went out in the Boston region, I think you have to assume that the water in your extra tanks have already been contaminated.

Hmmm, it does raise the question of how to clean the tanks once everything is back to normal and clean water is flowing again. Nothing that difficult, but not as easy as disinfecting a small plastic jug.