Ok, guys I am hoping someone can help me. I own a condo on the second floor of a 3 floor 12 unit building.

Every now and then there is a high pitched squealing/shrilling noise coming from the pipe(s) in the wall behind my toilet. It's driving me insane.

I can't exactly nail down what conditions cause it.

Here is what I have noticed:

1) The sound lasts about 5 seconds.

2) The toilet supply line (I think that's what the hose going from the wall to the toilet is called) actually vibrates when the noise occurs (this should be a big clue right?).

3) Best as I can tell the noise does not always happen when my upstairs neighbors use the toilet. Another words I don't always hear a flush before the noise occurs. But even though I can't say I am 100% sure it's caused by them--I am pretty sure--I can usually hear them walking (I assume in and out of the bathroom) when the noise occurs.

4) Nothing I do in my apartment seems to affect it the noise. If I flush, or turn on the faucet, or turn on the shower when the noise starts, there is no effect (it would seem if this was a pressure issue, turning on the water would make the noise stop or change immediately).

Any ideas? Is it a pressure issue? I would gladly call a plumber and deal with my HOA but I feel like this is one of those things where he won't be able to find anything, because I can't reproduce the noise on demand.

Does this answer have any merit?
[answers.yahoo.com]

I managed to record the sound recently, here is a short video: [www.dropbox.com]

Thanks.

i would suspect someone has a toilet fill valve that is causing the noise.
if you can hear the noise others in the condo association can hear it as well.
there is a possibility that you have a leaking flapper on your toilet and when it fills it makes the noise ???
trial and error will be the only way to find this..

Thanks guys, so am I getting you right?

I should check the upstairs neighbors toilet to start with? Because flushing my toilet when the noise starts has no effect (also it doesn't leak or anything).

How does the piping work behind the walls? Is it possible it's from a unit that's not above me or below me?



Edited 1 times.

noise does travel thru metal pipes..

I guess what I mean is, let's say it is not my apartment, since nothing I do seems to affect the noise when it starts.

But given that the water tube going to the toilet vibrates when the noise starts, what does that tell me? Are the toilets all connected to the same pipe? behind the walls? From downstairs and upstairs units?

there would be one main cold water feed going up. each unit should be teed off of it. and no, there will not be a cold water feed that picks up just toilets on all floors.
either i missed it or you did not say that your cold water pipe to the toilet vibrates.
so, try turning the shut off under your toilet off to see what happens. if the problem is yours then the noise will stop.