Hello,

A couple of months ago I moved into a new condo. The first couple of weeks all was well, but for a while now there has been an awful banging/knocking noise coming from my walls, that I assume is coming from the pipes.

It happens in the area near the laundry and smaller bathroom (next to each other). The bathroom has a toilet, sink, and tub/shower. It will happen seemingly randomly, and always when there is no running water in my unit (at least none that I can tell). There will be a loud banging/thumping for about 10-20 seconds (sounds like lots of rapid deep knocks) then it will stop. For the last two nights it has been happening literally every five minutes all night long and spreading into the day too.

I noticed today that if I turn on my sink hot water in the bathroom while the noise happens, then the noise stops. Then, if I turn the water off immediately, the noise continues again until it stops like it would otherwise. I also noticed that when I turn off the sink hot water (after using it while there is no noise) there is a slight knock sound, but it is much fainter and only happens once or twice, not in rapid succession. I don't notice the noise when I turn off the sink cold water.

It's driving me nuts and making it hard to sleep. I'm not sure if it's something related to my water heater or something in the stack of units I'm in (there are three units above me, I am on the ground floor).

Is this actually a water hammer, even though it occurs when I'm not using water? If not, what is it? What can I do about it?

Sorry for the very basic questions; I'm not a plumber, just someone starting to get very frustrated by this noise and unsure if my building maintenance needs to deal with it or if I need a plumber myself. I appreciate any help!

Thanks!

check the toilet.. if the flapper is leaking by and the toilet fill valve is doing its job of refilling the toilet when the water level drops a couple of inches, this can happen.

I was thinking the same thing. Put some food coloring in the tank, and see if it winds up in the bowl, without flushing.

Thanks for the response!

I don't think this is the case. I haven't noticed the toilet running, and we actually just replaced the flapper less than two weeks ago. I didn't have any food coloring in the house to test, but I did shut off the water supply to the toilet for a few minutes and still heard the knocking.



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Is the condo piped with PEX?