Sewers can be dark places, with things hidden out of sight, or at least out of lanternlight. Characters exploring a sewer may hear things from beyond the circle of light.

1. Chittering of rats in the distance.
2. Dripping can be heard, falling as steadily as a metronome.
3. Something roars loudly in the distance.
4. Something scuttling along the bricks.
5. Splashing steps are heard disappearing into the distance.
6. The scrape of something catching the floor of the sewer.
7. The grate of metal on metal.
8. The splash of something entering the water.
9. Unusually loud squeak that sounded to have come from a rodent.
10. Water is suddenly heard lapping against the channel.