I'm removing a sink that's draining to a 2" PVC stack. However, it appears that there might be another sink or shower connected to the same stack. (I live in a odd-ball house with 3 bedrooms and 14 sinks.) Is there a way of determining what else uses the same stack?
I was thinking of capping the stack and blowing a shopvac into the available opening and seeing which sink begins to gurgle. But maybe there's a better way to do it.