I have a feeling the OP was a spammer, but in case others come across this thread. In Chicago, it all depends on what you type of trenchless sewer work is going to be done. Lining of the sewer is allowed in most cases. Pipe bursting not so much, this depends on type of material being used as the replacement pipe, and location of nearby utilities. As for Chicago Plumbing code, it does not address the sewer, you have to talk to someone in the Chicago Sewer Department, and follow the Chicago's sewer and drain laying codes.