The entrance back up to The Serpent Sewer is the ladder at Loc ( 70, 16, -36 ) /waypoint 70, 16, -36.
Another entrance back up to The Serpent Sewer is the ladder at Loc ( 7, 32, 4 ) /waypoint 7, 32, 4
The entrance to the dungeon instance The Murkwater Nook is the grate at Loc ( 28, 32, 72 ) /waypoint 28, 32, 72.
Edgewater Drains is the lowest of the 3 Freeport sewer zones. It is made up of 3 levels with stairs running between all 3 levels at the north and south end of the zone. The stairs are connected to large rooms at each level with hallways running between each pair of rooms with occasional offshoots. The bottom level is almost entirely underwater, while the upper 2 levels are only ankle deep.