How do you locate leak in wall?

[itskris]

I have a leak in a wall opposite side of room from bathroom sink. It leaked some time after the running water. It doesn't even seem logical to have a water supply line in that wall. If the water is travelling to that point, how do you locate it without cutting several holes in the wall?
I can't get over the wall from the attic. Are there any methods plumbers use?

[FishinFoolFaron]

Infra-red imaging is helpful in locating water leaks in a wall. If it is a spewing leak rather than a drip, a stethoscope may help also.

[Catfishy]

It may be leaking above the sink wall and running across to the opposite wall via a beam or strut. Is it an outside wall? Could it be from a plugged A/C drain?

[fishingcacher]

I'm assuming your water heater is in the garage rather than in the attic. Is that correct?

[tboltmike]

It may be leaking above the sink wall and running across to the opposite wall via a beam or strut. Is it an outside wall? Could it be from a plugged A/C drain?

Exactly what happened to me.

The drain from the A/C run in the attic elbowed into a vertcial drop in the wall that has the bathroom plumbing. This was not a sealed fitting. The raw end of the elbow just sat over the larger drain drop.

Crud built up in the drop and it filled with condensate and over the top. What was interesting is that the drop came down wall in the space shared with the light switch. This solved the problem of why water was coming out of the light switch. The drop turned horizontal and went thru several studs before going into the sewer drain.

I fitted a tee where the run turned down in the attic with one "run" of the tee facing up. I capped this but didn't glue it. That way I can pull the cap and pour Clorox down the drain or have access to rodding out.

My compliments to you Catfishy for your stratospheric greens to posts ratio!!!

Go Ganders.