In North Jersey, Dirty Water Don dives into a toxic sewer line. In Mt. Vernon, Ramone and George try to fix a sewage-filled basement.

In Connecticut, Rick searches for a mysterious clog in a treatment plant's outflow pipe. In New York, George and Ramone struggle to clear a clogged reservoir. And in Cleveland, OH, Josh attends to a backed-up basin that threatens to flood downtown.

A Fatberg of wipes, toiletries and trash has formed in a North Jersey sewer pipe. The Cleveland crew find themselves knee-deep in a rain-ravaged storm sewer and Ramon discovers a huge sewer break threatening people's basements in Mount Vernon.

A mysterious clog backs up the entirety of the downtown neighbourhood's sewer line; the debris from a severe storm backs up a critical grit chamber; a restaurant grease trap is in dire need of cleaning.

An abandoned sewer line is overwhelmed by stagnant human waste; the damage from a massive sinkhole threatens to shut down the entire city's sewer system; a large clog could take down a city building.

Dirty Water Don repairs outflow gates at a treatment plant; Ramone and George discover medical waste lodged in a pump station; Rick deals with a disgusting grease trap at a meat cutting facility.