High-Pitched "ringing" tone in one wall

[diyretired68]

STUMPED. For the past few months, I've noticed a very light "ringing" in one upstairs wall of my home. It's a high-pitched, very steady tone that doesn't waver (so even and steady that I thought it might be electronic in origin) and is almost imperceptible. But the sound is slightly louder now (or perhaps I'm just more attuned to it now) so yesterday I put my ear to the wall where I heard it strongest, and it was very clearly inside that wall. Three or four feet in either direction from the spot, the sound seems to fades away.
This is drywall, there is plumbing behind the wall (but it's a few feet from where the noise is originating) and no electric wiring. There is also a vent in the outer roof roughly above the spot on the wall. But I can't think of any other potential causes of the high-pitched tone.
I believe it's a partition wall rather than load-bearing. It's only about 4 inches thick. On the other side of the wall is a commode room in the master bath, and I don't hear the sound on the other side of the wall, which is really weird. I also don't hear the sound in the wall immediately below, on the first floor.
Have any of you ever run into a similar problem, and if so, comments as to the fix, or at least to my investigation? I'm only concerned if it is something that could be potentially dangerous (electricity, fire, something mechanical?) I'm not running heating or A/C, it's not a malfunctioning doorbell
Thanks for your input, professionals.

 

[JoeD]

If you turn off all the electricity to the house does it stop?
If it does then turn each circuit until you find the one.

 

[bud16415]

Only way to know for sure is to cut a hole.

My luck the second I cut the hole the sound would stop and there would be nothing behind it. Once I patched it did drywall compound and tape and repainted it the sound would start again.

Hope you have better luck than me.

 

[diyretired68]

If you turn off all the electricity to the house does it stop?
If it does then turn each circuit until you find the one.

Thanks, guys. In the interim I came upon the solution by googling, maybe this will help someone else that runs into the same problem sometime: It was the plumbing. The pressure in the pipes was causing the high, steady tone (I would never have guessed that!). I had installed a bidet hose on a toilet on the other side of the wall (a few feet to the side of the noise) about 6 months ago. The bidet hose is joined to the main water line, and then the line continues to the toilet after it. The noise started a couple of months after that so I didn't make the mental connection.
The fix is to reduce the water pressure in the line. I gave the valve a very slight turn, not even an eighth of the way around, reducing the water pressure just slightly. And immediately the noise stopped!
I am familiar with pipes knocking, swishing, and screeching, but never a clear, steady high tone. Learned a new one, I guess. File this one away in the mental index file. Thanks for your help.

 

[bud16415]

Thanks, guys. In the interim I came upon the solution by googling, maybe this will help someone else that runs into the same problem sometime: It was the plumbing. The pressure in the pipes was causing the high, steady tone (I would never have guessed that!). I had installed a bidet hose on a toilet on the other side of the wall (a few feet to the side of the noise) about 6 months ago. The bidet hose is joined to the main water line, and then the line continues to the toilet after it. The noise started a couple of months after that so I didn't make the mental connection.
The fix is to reduce the water pressure in the line. I gave the valve a very slight turn, not even an eighth of the way around, reducing the water pressure just slightly. And immediately the noise stopped!
I am familiar with pipes knocking, swishing, and screeching, but never a clear, steady high tone. Learned a new one, I guess. File this one away in the mental index file. Thanks for your help.

Many years ago at work I took a course called (Analytic Trouble Shooting). They gave an approach to solving problems that took a variety of steps. One of the first steps on the checklist was to ask, What has changed?



A high percentage of problems happen around or after something has changed in your case the new line you added. They then taught us to ignore what we think we know about if the change could be the source of the problem and just look at that one element with fresh eyes.



I remember once a machine went down regulary that was pretty complex and a dozen experts were standing around thinking of all the things that could have been the issue. I went over to the operator of the machine who knew nothing of the workings of the machine and asked him if he had noticed anything out of the ordinary. He said it had been working really good right up until it stopped, but about a month ago he told his boss that it didn’t sound the same. The thing was normally so noisy and the boss came over and listened and told him it was working fine its always sounded like that. I said where do you think it sounded odd and he said down in this area. Sure enough we opened that area and found the problem a motor bearing was going and overheated and shut it all down as a cascading series of events. I always trusted a lot in how someone that works with something can feel a change that no one else would feel.



A good starting question is to say what has changed?

 

[Eddie_T]

I am still wondering how pressure alone could cause the problem. I am thinking maybe a small unnoticeable oscillation with a toilet float.

 

[JoeD]

It must have been leaking. Water under pressure just sitting there would be silent.

 

[BuzzLOL]

It must have been leaking. Water under pressure just sitting there would be silent.

My guess also... a valve/regulator was seeping water...