Bathroom leak? Follow these steps before calling for help.

I’m reposting this from 2007. 
I’m not sure what prompted me to write it then, but today it’s because I’ve gotten two of these calls this morning from able-bodied folks who could’ve used the advice earlier.

Please read on:

We get lots of calls from people just like you with a century old home and the ???it???s-raining-from-the-ceiling??? story. One of the first questions we ask is ???Is there a bathroom above????   Ten steps to identifying a bathroom leak: Plug the drain as if you were going to fill the tub. Run the water from the tub filler only, using either the hot or cold water, but not both. Check for leaks. Do the same thing using the other temperature of water, either hot or cold, but not both. Check for leaks. Now turn on the shower head using both hot and cold water and let it run for a minute or two. Be particularly careful not to get water on the walls or outside of the tub enclosure. Check for leaks. Now you???ve got a few inches of water in the tub. Let it drain. Check for leaks. Now you???ve tested the valves in the wall, the connections to the shower head and tub filler and the drain assembly. If it isn???t leaking now, the problem isn???t with the plumbing. Take a bucket of water, or use your handheld sprayer if you???ve got one, and completely wet down the walls of the tub enclosure. Splash or spray the water directly onto the shower faucet and all along the seams where the tub meets the walls. Check for leaks.   Bad tile grout is a sieve, but even a good tile grout job will be somewhat porous.   If this doesn???t expose your problem, flush the toilet 3 or 4 times and check again. Still nothing? Run the basin for a few minutes. Check again.

Of course, if you’ve got water coming from the wall or ceiling at any point during this test, then you’ve found your leak.  Still nothing? Then you???ve got trouble.   A plumber will have to come and make some holes in the ceiling where the leak is showing up. From there he???ll have to follow the water marks to their source. On the bright side, you were probably going to have to replace that section of the ceiling anyway. Mold will have grown on that wet sheetrock. Mold???s no good.   Good luck, homeowners.    Master Plvmber