I manage a new apartment complex and have a resident that has a vibration in an interior wall in the half bath. The vibration starts at 4 in the afternoon and gets louder and is intermittent. He hears it whether the A/C condensors are on or off. He has lived here a year and it just started.

There are 12 units in his building, and he located above the electrical panel. I have the builder, electricians, a/c folks and 2 maintenance men trying to find solve the problem. It is in a wall where there are no pipes, electrical lines. On contractor felt that it was coming from the electrical panel and nothing could be done. The resident is upset that I can't solve the problem.

Any suggestions? It is not coming from a/c, water pipes or electrical unless it is from the panel below his unit... no attics, no vents on the roor, tankless water heaters in the gargage.. HELP please.

Go into the apartment when the noise is happening. Then you might uncover the cause.

Thanks for the suggestion, there isn't one directly below, but we went in that one, the one next to him, and the one across the hall from his, and in all the garages below or near his, no noise.

Below, next door... no matter: You have to go in when the noise is happening. The maintenance guy needs to hear it for himself - and troubleshoot it from there.

Describe the lay out of the unit. Then describe the relationship of other units to this unit . Better yet make and post a drawing.

Below, next door...no matter: You have to go in when the noise is happening. The maintenance guy needs to hear it for himself - and troubleshoot it from there.

Yeah there were 6 of us there yesterday when it was happening and didn't hear it in any other unit.

Yeah, Crazy. If no one is there then the noise won't happen. Call the maintenance guy right away if it happens again.

It is not coming from a/c, water pipes or electrical unless it is from the panel below his unit... no attics, no vents on the roor, tankless water heaters in the gargage.
I have a question. If you can't tell us where the noise is coming from how can you be sure of where it's NOT coming from? Back to you, Tom