Located in a literal pump station in Gary, Indiana — the southern edge of the GLMZ — The Sump is what drinking looks like when infrastructure gives up. The pump station was built to manage stormwater overflow and abandoned when the Gary municipal water system was absorbed by Zheng-Dao. Someone cleaned out the main pump chamber, installed a bar made from a water main section, and started selling drinks. The pumps are still in the room. They don't work, but they're too heavy to move, so they've become furniture. The floor is perpetually damp.

The Sump attracts the hardest crowd in the southern corridor: salvage crews, infrastructure scavengers, and the kind of independent contractors who don't list their specialties on public registries. The bar serves exactly three drinks — beer, whiskey, and something called Runoff that nobody has successfully identified. Fights are common but brief; the damp floor makes traction difficult, which tends to resolve conflicts through mutual embarrassment rather than injury.