Water Hammer?

[Baddad]

I’m getting a loud humming or groaning noise for 15-20 seconds after flushing a toilet on the ground floor of our house. The noise starts right after the toilet finishes refilling. It mainly happens on one toilet but sometimes on another. It’s not a banging noise. More like a strong vibration. It does not happen when we flush the third downstairs toilet.

Is this water hammer? How do we fix it?

 

[Jeff Handy]

Sometimes the shut-off valve for a toilet supply to a fill valve is kept partially closed.

This is usually to make the toilet fill up more quietly, or more slowly to avoid possible flooding if the fill valve sticks to always on.

This can make either the fill valve or the shut-off valve get noisy, as water squeezes through some tight little spaces.

See if you can open up the supply stop valve all the way.

Otherwise, you should probably just replace the fill valve, very cheap and easy to do.

You can find a million videos of how-to on Youtube.

 

[Jeff Handy]

The groaning is probably the last quarter inch or so of water trickling through the fill valve, until it finally turns all the way off.

A clogged up fill valve can get this problem.

But also, if the incoming volume and pressure of water is reduced by a partially closed supply stop valve, the fill valve sometimes does not get enough pressure to initiate a firm and solid stop to the refill cycle.

 

[Diehard]

Totally agree with Jeff except I've had that same type of noise happen as you described even when the water supply was fully open. Those flush valves either get worn and/or pick up a little crap in the water to effect there closure noise.
A new flush valve is a good option and you can do it yourself, guaranteed.

Oops...Looks like Jeff squeezed in another comment while I was typing. I'm slow.

 

[Baddad]

Sometimes the shut-off valve for a toilet supply to a fill valve is kept partially closed.

This is usually to make the toilet fill up more quietly, or more slowly to avoid possible flooding if the fill valve sticks to always on.

This can make either the fill valve or the shut-off valve get noisy, as water squeezes through some tight little spaces.

See if you can open up the supply stop valve all the way.

Otherwise, you should probably just replace the fill valve, very cheap and easy to do.

You can find a million videos of how-to on Youtube.

 

[Baddad]

Thanks for the replies. Just to clarify...the noise is not coming from the toilet. It is coming from inside the wall. Definitely old toilet hardware so I’ll replace see if that works.

 

[frodo]

I’m getting a loud humming or groaning noise for 15-20 seconds after flushing a toilet on the ground floor of our house. The noise starts right after the toilet finishes refilling. It mainly happens on one toilet but sometimes on another. It’s not a banging noise. More like a strong vibration. It does not happen when we flush the third downstairs toilet.

Is this water hammer? How do we fix it?

try this terlet hack and see if it works
reach under/behind the terlet and close the supply valve just a little/ flush/ little more..

see if that helps you out

 

[Jeff Handy]

A noise like that is hard to pinpoint the exact source.
It might sound like it comes from the wall, because the pipe in the wall is carrying the sound back there, and the enclosed space acts like a speaker box.

Adjust the shut off valve and/or change the toilet fill valve, then see how it goes after that.

 

[frodo]

humming is caused by pipe being strapped to tight
or
bib washer loose
or
ceramic disc loose or wore out

banging is caused by loose pipes

tinkle tinkle
is caused by solder,rock, foreign object moving in the pipe

rumbling is what the water heater does