The Hufflepuff Common Room can be found by entering a door to the right of the main staircase in the entrance hall and descending a flight of stairs. It is located near the kitchens and is hidden behind a still life painting. Hufflepuff pride is evident in the cheery shades of yellow strewn about in different hangings and furniture. The chairs are squashy and comfortable with tables and sofas scattered about. A fireplace is located to one side of the room. On either side of the fireplace are two tunnels that end in perfectly rounded doors - one leads to the girls' dormitory while the other leads to the boys'.

Accessed through a tunnel that leads to underneath the Black Lake, the Slytherin common room is dark and cold. It is dungeon like in appearance, with low ceilings, greenish lamps and furniture and skulls everywhere. Candles sit on almost every surface, their wax having dripped into piles underneath them. The fireplace is lit with a blue-green flame, though it doesn't offer much warmth. A small iced over pool is located to one side of the room. If a student is lucky, they could catch a glimpse of a mermaid. A bit farther from the pond is a pair of tunnels that lead to the girls' and boys' dormitories.