Of course it's the sewer level.

There was a sewer level in the Episode III movie as well, but it ended up on the cutting room floor.

The trip through the planet core in Episode I was also a sewer level. And Kamino was kind of a sewer planet. As is Dagobah, really. So yeah, all six movies. We trust Disney will maintain the tradition.

Transcript

GM: As I was about to say: You're stuck in a horribly stinking chamber. There are shards of twisted metal littering the floor, which is ankle deep in filthy water.
Han: Cool! I search for treasure.
GM: Roll for Nausea.
Luke: Oh great. The sewer level.
R2-D2: The plans show this is a giant composting bin for the memorial gardens.
Leia: Ew. Well, it could be worse.
GM: Something slithers past your legs.
Luke: Let me guess, giant rats.
Leia: {aside, softly} It's worse. So, so worse.
C-3PO: No, it's a dianoga!
Luke: What's a dianoga?
Han: It's a pair of—
C-3PO: A giant native Naboo earthworm!
C-3PO: With a big eye on a stalk!
Luke: Gross.
C-3PO: Don't worry. It won't compost you unless you're dead.
Leia: So we'll be fine for, like, another ten minutes, then.