Next guy was more experienced and used water jetting to clear the blockage. 

The line may need to be flushed if there is a blockage the scope cannot see past.

His suggestion was to rip out the plaster walls to trace the pipe to either replace the piping or determine the location of the blockage so it can be addressed.This sounds very drastic and expensive to me. 

If the tenant causes the blockage, its on them.

A drain tile test was done and showed a 50% blockage in two of the tested sites and 75% at the third.

A drain tile test was done and showed a 50% blockage in two of the tested sites and 75% at the third.

Ideally, the plumber would either feed the camera in through the toilet or take the toilet off the flange and feed the camera down into the drainage hole until it reached whatever blockage there was.

When you go to turn the water back on it is possible to break off the rust causing a blockage or loss in water pressure. 

Maybe if he can go from a downstream clean out and look up to see if there is a possibility of clearing the blockage, then you can try to get it lined....but I'm guessing you're going to be back to your original options to address this.

I spent all day beating myself up because I have replaced roof after roof after roof after roof, and every single firggin time, they destroy a part of it by re-installing a friggin dish that wasnt even in use, because of some brain blockage I apparently suffer from.