It never rains but it pours. Isn't that what they say? And if it hadn't been for all the rain we've had recently...
Well, I suppose if it hadn't been for the rain, we wouldn't have known about the problem... yet.
Whatever the stuff is that was used to seal the hole where the main water line comes into the house had deteriorated.
And the heavy rains we've had means that the water table has risen high enough that it's been pouring into the wall.
But I'm so thankful that the problem showed up while the room was mostly empty. This used to be my sewing room. If all my fabric was still piled up against that wall, it might have taken months to notice it.