As suggested previously, I was suggesting powering down every breaker, then only energizing one circuit at a time until the sound occurs. Keeping most of the house unpowered reduces background noise, perhaps allowing a more precise characterization of the sound and perhaps the source.

I'll try that sometime. I'm still not sure it'll help very much because, like most of the breaker boxes I've ever lived with, mine is horribly labeled. I replaced a light switch last week and it took me 7 tries to find the right breaker. I might be surprised, though. If the lights go out in the bathroom and I still hear the noise, it'll tell me that it's not in the bathroom. Although if it is something in the bathroom, I'm not sure what it would be...

If you go through the process of powering down every breaker, you can take the opportunity to label them more clearly.

I'm still really curious as to what it is. It *sounds* like a pump of some kind to me. But you said you were sure that your house doesn't have a pump to keep the water pressure up on the third floor.

Ha! True. The tough part there is in knowing exactly what is getting turned off/on. Sometimes it seems like an outlet in one breaker actually belongs to another one. It'll be a bit of a chore depending on how detailed I want to get But you're absolutely right. This might be worth the effort alone.


We don't have anything for water pressure, but we have a valve in the wall for our shower. It's an electronic one that's controlled by a digital panel. I've never fully eliminated this valve as a suspect, but I know exactly where it is in the wall, and if I put my ear directly next to it the sound isn't any louder.

Do you have any line voltage smoke detectors?

My Panasonic IP phone makes a similar noise. I can only sometimes notice it.

Yeah, highly suspect.

The only (ONLY!) way to know for sure, is to turn off the breaker that provides power to that valve, and then see if you can still hear the noise.

Only if that valve is the only thing on that breaker.

I don't really understand ; finding the correct breaker will still not tell you what is actually causing the sound, will it? Especially not if you don't know where the circuits run throughout the house.

I don't think you're wrong. I guess the idea is that it's one more piece of data, and more data is always helpful. This would at least tell me for sure if the noise is caused by something that's on the same circuit as the stuff in my bathroom. If it isn't, then that's useful information. If it is...then I'm not sure what to do

Once you know what circuit is powering the noise source, you start pulling wiring connections in that circuit apart until you identify the single device that is the actual source.

Always leave the White and bare ground wires connected within the electrical boxes. Disconnect the selected power wire (typically black, sometimes red) with the breaker turned off. Then engage breaker, determine what has been disconnected (no longer has power) and whether the sound has changed.

Disconnect breaker again before inserting fingers or tools into the electrical box.

Easier to just run around with a pluggable lamp in hand, going from outlet to outlet to trace most of the circuit, and using wall switches for most everything else.

Nothing is permitted to be "hidden" by code, so it all should be doable without raising the level of competency/risk required.

Cheers