Dave -
No idea what it is, but it probably doesn't matter. As long as
the flood water didn't reach the top of the necks on the carboys, I
would think the wine inside should be just fine. Mold and other stuff
can't get through glass, so as long as the water stayed below the top
of the neck, you should have no worries (at least on that front). You
might want to freshen up the airlocks with new pot. metabisulphite
solution, if you feel a need to do something. I'd rinse off the
chlorine solution, too, as long as you're at it. It should have
killed whatever was there, but once that's done, you don't need it
longer term.

Condolences on your flooded basement -

Doug

> <<snip>>... the basement flooded. Of course
> it happened while I was out of town. So when I came back this weekend I
> discovered what looks like a white mold over the outside of the carboys. It
> forms a speckled pattern, if that helps.
>
> Any idea what it is? I washed the carboys off with a chlorine solution.
> Will that kill it? Do you think the mold could have made it into the wine
> itself?
> <<snip>>
> Dave