Downing the Drainpipe
We have a 3″ schedule 40 PVC drain from a bathroom that runs about eight feet down through the basement. When hot water is draining from the bath, there is a loud cracking sound generated in the drainpipe. What can I do to the drainpipe to reduce the noise?
The “cracking” noise is the result of expansion and contraction of the PVC pipe as it heats up and cools down when hot water is run through it. While there is a host of means to deal with this problem, we believe that the best solution is to replace the PVC with a section of no-hub cast iron. Use no-hub couplings to connect the cast iron to the PVC. You will not only be rid of your cracking noise, you will hardly be able to hear water running through the new pipe.