I have a 1960 ranch home with a crawl space and septic system. The plumbing is pretty simple, but I'm putting an in wall clothes washer drain, and I'm not sure if I need to, or how to vent it. The current vent pipe is Galvanized. Hopefully someone could give me advice on the setup.
I was thinking.
A. 2 inch drain pipe, S trap, no vent, into main drain
B. replace galvinized stack with pvc, and possible add a vent for the bathroom sink or clothes washer