Rumbling When Toilet Flushed

My wife and I just moved into a newly built house about 6 months ago. This problem has existed from the day we moved in. Whenever solid waste or even toilet paper alone is flushed down the toilet in the master bath (on the second floor), there is a loud rumbling sound heard several seconds later in pipes that seem to be running inside of a first floor wall. It sounds like thunder and only lasts a few seconds. To me, it sounds as if this sound is created as the waste passes down through the pipes. I am not a plumber, but do have some basic knowledge. I am sure that this is not a problem with the ballcock or with the supply lines, or with water hammer. Something is causing this rumbling sound as the water/waste moves down through the pipes. There is another toilet in a another bathroom on the second floor, but this one does not cause the same rumbling sound when flushed. Any explanation for this sound and possible fixes would be much appreciated. Thanks in advance

Just a shot in the dark here.

Is it possible the verticle stack is not fastened properly? So that when the large amount of water hits an offset in the wall or floor/ceiling, it could be moving.

Another possibility, sometimes, if there is an AVV in the line, it may flutter when discharging large amounts of water (Its probably unlikely)

Did you ever found the solution to this issue? I just moved into a new house and this exact same problem is happening to me. New build, 2nd floor toilet, only happens to this one toilet, only happens when flushing solid/toilet paper. Thanks

https://terrylove.com/forums/index.php?threads/toilet-flushing-causes-pipe-rumblings.12429/

Being a new house, sometimes glue to welt the joints on ABS or PVC gets to be too much and possible causing a partial blocking. I'm more inclined to think it's a vent issue. To eliminate any thought that it is from the water line, fill a bucket full of water and dump that down the toilet. Check in the attic if there is roof vented. If no vent then its an AAV. Check under the sink.

WorthFlorida said:

https://terrylove.com/forums/index.php?threads/toilet-flushing-causes-pipe-rumblings.12429/

Being a new house, sometimes glue to welt the joints on ABS or PVC gets to be too much and possible causing a partial blocking. I'm more inclined to think it's a vent issue. To eliminate any thought that it is from the water line, fill a bucket full of water and dump that down the toilet. Check in the attic if there is roof vented. If no vent then its an AAV. Check under the sink.

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Thanks! I have tried turning off the water and pouring water down the toilet and the rumbling sounds still happening. It's roof vented; haven't checked for blocked vent but water seems to drain good, no bubbling or gargling.

I find that most homes with upstairs plumbing will make quite a rumble when a toilet is flushed. It's not a new thing.
If the waste line is in a 2x4 wall the pipe is likely touching the drywall, transmitting the sound of water rushing down the line out to you.
The 3" fittings stick out beyond the 2x4 and the drywall pushes up against the fittings.

Cast iron drains are still a premium upgrade...they tend to be much quieter than plastic drains. They're harder to work with primarily because they're so heavy, but cutting is a bit slower, too. But, today's nohub pipes are easy to make the connections versus the old leaded hub connections.

I have this exact same problem. New home built only a year ago, and it only happens when the master bathroom toilet is flushed. The more stuff in the toilet, the worse it gets. Mostly rumbling and banging. Anyone find out what it is?

jsmlee1207 said:

I have this exact same problem. New home built only a year ago, and it only happens when the master bathroom toilet is flushed. The more stuff in the toilet, the worse it gets. Mostly rumbling and banging. Anyone find out what it is?

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No, the plumber subcontracted by the builder don't know what the problem is. And since it's the middle of the winter they are not able to check the vent on the roof. They were thinking it's the toilet and planning to change it, but with the virus thing going everything is on halt.

By the way, for me, the rumbling sounds apparently happening to both upstair toilets (master bedroom and the other bathroom that's 40ft away).

Franky said:

By the way, for me, the rumbling sounds apparently happening to both upstair toilets (master bedroom and the other bathroom that's 40ft away).

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Yes, every home I've been in with upstairs bathrooms and plastic pipes will sound like that. You can rip out the drywall and replumb with cast iron piping.

Terry said:

Yes, every home I've been in with upstairs bathrooms and plastic pipes will sound like that. You can rip out the drywall and replumb with cast iron piping.

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Thanks Terry! Yes, seems like all the discussions I have found didn't really found anything concrete/solution, nor heard any further deteriorations causing damage, which is my main concern that something will eventually break and cause leak;
The rumbling sound is more of an annoyance for me. I assume most other house owners probably just gotten used to it eventually.