Turns out she never had anyone look at the pipes from her bath, even though my landlord had asked her to on at least 3 separate occasions last year. Every time she takes a bath (about once every 2 or 3 months) I have water coming in through my ceiling. Anyway, now that I own the place, she will be getting her plumbing looked at. If it happens again, I'll take her to court to get it fixed.
Did I mention the cranky thing?