Recently we had to have a portion of our basement floor excavated due to an oil spill, and as part of that they needed to dig under one of the interior walls, including under the "lolly columns."
After all of this was completed we noticed that following just about any rain we were getting some foul-smelling, dark brown drainage out of an opening in a 3-inch diameter cast iron pipe. We had never had that before, and in fact we didn't remember even seeing that pipe before.
We are guessing that this is drainage from the sewer vent. We certainly don't want to just leave this as is, but we don't want to cap it either until and unless we know that is OK.
Does anyone know how this should be handled?