My wife found a leak from the master bath shower stall into the ceiling of the half-bath on the first floor, yesterday. I spent soem time ripping the ceiling in the half-bath apart, then called for reinforcements. There's a big hole in the ceiling now, the shower drain is the culprit, but it's not a big leak. My cousin (the retired police officer) has an in with a plumbing company in the area, and we'll be getting a few estimates on the repairs soon. We may have to spring for a new shower stall . . . !
In the meantime, the hole in the ceiling has caused a pretty big draft into that half-bath, so we closed the door.