The original post raises an interesting question that I can't answer, and I'm not sure there is much or any
real science on it. That is, the TB bacteria is reputed to have a long dormancy so it can still be infectious
years after blood or sputum from a patient is swabbed into a crack in the floorboards, etc. I think there is
some truth in this. On the other hand, many buildings that were used as TB hospitals in the early Twentieth
Century have gone on to be used as homes, hotels, and for other uses. I've never heard of an outbreak of
TB from such a source. It is always passed by exposure, usually airborne, from a TB patient to others.
So, are very old estate pipes a peril in this way? I'm dubious, but it seems true that at least in a petri dish,
very old TB bacillus can grow after years of dormancy.