"We're taking on water!!!"

"We're taking on water" is a routine operation on a steam locomotive....on a ship the phrase can have a much different "intensity." In a house, well it's a precursor to a long night of scrambling to keep everything that isn't yet wet dry, cleaning up the water, pitching the unsalvagable, and then figuring out where the water came from in the first place.
We've been in this house almost six years and through some heavy rain storms, hurricanes, and the like we've never had a drop - not even a puddle - of water in the basement....it had gotten to the point where I turn on the sump pump every month or so just to make sure it's still there.
Last night I went into the utility room to start setting up my new "toys" when I heard a "Squish" as I walked across the floor. Looking down I could see a large section of the floor was wet. I have two shelves in that room where I store some of Christine's blank artists canvases - and my stash of unbuilt resin car kits. The stuff on the top shelf was soaked. The instant I noticed this I heard a yell from the powder room directly above where I was standing "Honey, the floor is soaked!"
I really don't know what the source of the water is, or was, although I suspect it's the supply line into the toilet or sink in that bathroom. I've turned the water off to both of them and will investigate further this afternoon.
Damage to the unbuilt kits could have been much, much worse. I wasn't concerned about the resin parts, since they're pretty immune to water. Decals, on the hand, are another matter.
Some of them are unsalvagable, the rest are sitting away from the soaked kit boxes and (hopefully) will dry out and still be usable.
What a mess.