Best Of

once the coating inside breaks down , iron pipe will corrode, develop scale and rot through

Aggressive. Low ph water can do that.

All piping materials have pros and cons.

The OP needs to define “best”😉

sounds like they tied into a 2” drain or vent pipe?

Is it clogging up, or why the concern? It needs to be 3” for a toilet, by code.

if you're putting string down the drain it is likely to get tangled on something regardless of material.

No-Hub cast iron has always been the top shelf material here and of course, the plumber installing it has to be of equal quailty as well.

No-Hub cast iron drains, ABS vents. For commercial work or houses over two stories, the materials had to be all metal, so we used DWV copper for the vents.

In the beginning, we used a chain snapper to cut the cast iron, but then transitioned to a chop saw as it was faster and the cuts more accurate.