Sewer C

The Sewer C is a location in Luigi's Mansion 3. It is found in the Boilerworks on the second basement floor of The Last Resort, located north of Sewer B and east of the Drainage Control.

After Gooigi opens the spiked gate of Sewer B, he has to keep going into the pipes while Luigi travels with the duck floaty. There are pipes that will splash water down on Gooigi. When Gooigi gets past the pipes, Luigi needs to vacuum a chain ball to reveal a green pipe. Gooigi needs to dodge more water pipes before he opens the final gate.

After Gooigi opens the final gate, Goobs with shark fins will attempt to pop Luigi's raft. After the water is drained, Luigi can use burst to remove their swim gear and capture them. There is also a buoy that Luigi can flash with the Strobulb. There is also a chest behind some bars that Gooigi can get through. There is a pipe next to a malfunctioning light that Gooigi can go through after using the Suction Shot on it. It leads to a submarine where Gooigi can make the purple gem appear by lighting a stove with a piece of burning wood. The water must be drained before doing this.

When Luigi and Toad enter this room, a Slinker will appear by rattling the cages.