That is an old lead fit-all that is busted. It is the access the plumber needs to access to power rod your drain. Did you call the City to as them if their sewers are draining OK? If they say they are clear its time to call a plumber. I was just up North Wests side today, lots of flooded basements.
Cass: If your a Chicago, or Illinois licensed plumber there is none. But if you are just a sewer and drain cleaner guy you need to have a Cook County sewer license which is 50 bucks a year. To get it you have to take a test the first time out. It a Sewer and Drain layer license. Mine is SL#340 We had that number since the 1960's We keep it casue it makes getting permits for sewer repairsin the streets of Chicago a whole lot easer.