The day is young!

It happened the day before, since children were still playing. We are safe.

My impression was that it had happened several days to a few weeks prior. Enough time for the house through ordinary daily activity to largely exhaust its water reserves. Of course most of today's actual houses don't keep that much on hand, but it sounds like this one had a sizable store at one point.

Sure, I should have said "at least the day before"