Water will always run to the lowest point before leaking out. If it appears to be coming from above the Chloroplast, I'd start with anything accessible from the inside. Tub, sinks, etc. If you can't find anything there then cut a access hatch in the underbelly (3 sides of a square) and then pull the flap down and shine a flashlight up in there to see if you can pinpoint where the leak is coming from.
Once you've found out, determine the best way to address. If it's something small and obvious you may be able to get away with another access door. If not, you may want to consider dropping the underbelly. It's a two man job or more getting it back up in place.