Mystery of the cattery pond... When Debbie went down to our basement cattery this morning, she discovered a small pond in the northeast corner of the room. This was very reminiscent of the indoor ocean we had last summer during a rainstorm, but on that memorable occasion it was quite obvious where the water came from: the casement window had about 8 inches of water in it, and water was streaming through the window frame into the basement.
This time the source wasn't nearly so obvious. We cleaned up the water with mops; the total was about two quarts. That's far too much for a cat to be the source under even the wildest set of assumptions. It's even too much for a water bowl to have been the source. The kitties were puzzled as well; it was not the water feature of their dreams. So we were mystified as we cleaned up, until Debbie spotted some water on a casement window sill. Ah, ha! That had to be the source. But how? The bottom of the casement well had no water. Where did the water come from? How did it get through the window?
Some inspection and thought unveiled the answer. If water came through the casement opening at an angle (as it would if the wind was blowing from the east), then the rain would strike the casement window pane. Then it would run down and into the sill that the window slides in. That sill has a drain to the outside, but it's a small hole – heavy rain could easily overwhelm it. In that case, water would overflow and some of it would run down the inside of the sill, into the cattery. That must have been what happened. It was rainy and windy last night.
I'm going to call that a mystery solved. We've been in the house nearly two years now, and this is the first time anything like that happened. Let's hope it remains a rare occurrence!