The question still stands
If you were me and had limited plumbing knowlwedge would you:
The pipe is cast iron where visable and is 50 yrs old. I have 4 ft currently exposed which does slope at least the minimum 1/8" per ft. I have been in the house for 3 yrs and have had no drainage issues.From my stack to the city sewer is about 90 - 100 ft.
A:take your chances and use chemicals periodically
B:Call in a plumber explain the situation and have him diagnose? If so what questions should be asked?
C:Dig up the concrete myself and relace the cast iron with pvc.
Thanks for your replies.