Can I drain my washing machine into a 4" diameter cast iron stack? I want to take my washing machine out of the basement and reinstall it in kitchen above. I would like to drill into the stack to take 1 1/2" pvc drain pipe. The washer drain is 8 feet from the stack. It's currently using trap, and back up valve.
I think you are going to have more difficulty drilling into the cast iron stack, than routing a new pipe. Follow the route of the stack down with your 2 1/2 pipe, and then feed it into your waste water system, using the correct fitting