Mary, the soap jugs you've mentioned should be
fine to reuse for water. I think I filled those back
when I was preparing for Y2K
or some such.
I added 2 or 3 drops of Clorox to each
one for storage. I also used empty Clorox jugs, etc.
I think you're wise to plan ahead. If not needed for
a Hurricane this year, just think how much water
you've got to water plants with.