When i flush the toilet upstairs, you can be sitting in the living room and it sounds like a waterfall coming down behind you in the wall. Very loud, what can i do? I am trying to sell my house, and this isn't going to work/

Hasn't it always sounded like this or is the sound new? Flushing a toilet causes about 2+ gallons of water to rapidly drain down a 3-4" pipe inside your walls, this causes some noise. That noise is louder if your drain lines are pvc or abs as opposed to cast iron.

Well, I guess it's always been there, but it didn't sound as loud.

Most likely ABS or PVC pipe. Not much else to do except cut the wall open, jam pack it with fiberglass insulation and close and patch. If this is a very small wall section, plumbers will sometimes put hardieboard and drywall over the existing wall. Increases the STL fairly well.

Thank you for your help. I'm not employed at the moment, so trying to fix the house up is hard right now. If I get employment hopefully in the near future, I will act on what you suggested.

Sorry to hear about unemployment and good luck with the house. I had a similar situation in a wet wall where a 4" ABS pipe ran. Opened the drywall, furred out 2", packed in fiberglass and put in a piece of 5/8 drywall. Jog in the wall, next to the door, is called "an architectural detail" and is virtually unnoticed. Very quiet

Had the same problem years ago. Pulled off the paneling, furred out the wall another inch or so and wrapped the ABS drain pipe with rubber backed carpet. Since then I replaced the paneling with drywall. You can't hear a thing now when the toilet is flushed.

Another good idea! Brian

I think the best way is to replace that vertical drop with Cast Iron pipe. It will run you about $60.00 for the pipe $12.00 for 2 Fernco couplings and you can do it yourself as weekend project.

But unfortunately, if the pipe is in 2"x 4" wall then you may hear some noise it even with Cast Iron pipe.