Loud Pipes

My main drain leading from the roof to the basement passes through the wall that separates the kitchen and the living room. When the toilet is flushed, or the shower is running in the second-floor bathroom the falling water makes a lot of noise. Is there anything that I can do to reduce or eliminate the sound?

When drains work properly, water swirls around the edges of the main drain pipe on the way to the basement, rather than falling down the middle. When it does fall down the middle it makes a lot of noise. Most new houses have plastic pipes that are less effective at muffling the sound than old cast-iron pipes. The only solution I have is to open the wall and fill the cavity around the plumbing stack with fiberglass to muffle the sound. If you are lucky enough to have the pipe run alongside a closet wall, go in through the closet to minimize the wall repair job.