Our washing machine drain overflows each time the machine drains -- I have snaked, used a pressure cuff with the garden hose, and tried Drano. The drain pipe is cast iron from the 1950s -- I'm wondering whether it has just corroded inside to the point that the internal diameter is partially occluded. Anything else I should try before I open up the cast iron pipe and try to replace it with PVC?
Thanks!:confused: