In Brooklyn, Dirty Water Don repairs outflow gates at a treatment plant. In Massachusetts, Rick tackles a grease trap at a meat cutting facility.
In Mount Vernon, a mysterious clog backs up a downtown neighbourhood's sewer line. In Cleveland, the debris from a severe storm backs up a critical grit chamber.
Don dives into a toxic sewer line. Ramone and George try to fix a sewage-filled basement, and Josh tries to break down a rock-solid formation of grit and fat.
Don tries to remove a massive 'fatberg' of wipes, toiletries and trash blocking a residential sewer line. Plus, Ramon discovers a huge sewer break.