Sewers of Waterdeep

Do you smell it? That smell. A kind of... smelly smell. A smelly smell that smells... smelly.

Subterranean waterway, sanitation

Below Waterdeep. Sewer lines do not necessarily follow roadways.

Clean and well-maintained, as medieval sewers go.

Huge - the sewer network has roughly the same footprint as the city itself, but with many secret passageways.

Stone

Sewers are maintained by the Dungsweeper's Guild, who also keep maps of the sewers on file.

It'd make sense for their maps to be the as-builts, but this is unconfirmed, as it's never occurred to us to ask.