Washroom

• Type: Lavatory, Bathroom, Public Convenience
• Location: Various, most notably within Hogwarts School of Witchcraft and Wizardry and the Ministry of Magic
• Owner/Residents: Varies by location; typically the institution in which they are located. Some are known to be haunted by ghosts.
• Key Features: Often appear similar to Muggle washrooms but can possess magical plumbing, secret entrances, enchanted fixtures, and other unique properties.

Washrooms, also referred to as lavatories or bathrooms, are a common feature in the wizarding world, serving the same basic function as their Muggle equivalents. However, many wizarding washrooms are distinguished by their magical characteristics. At Hogwarts, for instance, washrooms are not merely functional spaces but are entwined with the castle's long history, sometimes housing secrets, ghosts, or hidden passages unknown to most students and staff. These locations are often settings of great secrecy and significant events, as their inherent privacy makes them ideal places for clandestine meetings, brewing forbidden potions, or hiding from threats. The plumbing itself can be enchanted, as seen with the taps in the Prefects' Bathroom or the toilet-based entrance to the Ministry of Magic.

Despite their mundane purpose, washrooms are the setting for numerous pivotal moments throughout the series. They function as narrative hotspots where characters find themselves in peril, make crucial discoveries, or engage in dramatic confrontations. Key events include Hermione Granger being attacked by a mountain troll; the year-long brewing of Polyjuice Potion; the discovery and opening of the Chamber of Secrets; Harry Potter deciphering a vital clue for the Triwizard Tournament; a near-fatal duel between Harry and Draco Malfoy; and the infiltration of the Ministry of Magic. These events underscore the surprising importance of these seemingly ordinary rooms.

• First-Floor Girls' Lavatory: The site where Hermione Granger, hiding after being upset by Ron Weasley, was cornered and attacked by a mountain troll let into the castle by Professor Quirrell. Harry and Ron saved her here, an event which solidified the Trio's friendship.
• Moaning Myrtle's Bathroom: A second-floor girls' lavatory that is permanently out-of-order. It is the haunting ground of the ghost Moaning Myrtle, who was killed there by the Basilisk. This bathroom holds the secret entrance to the Chamber of Secrets, which is opened by speaking Parseltongue to a specific tap engraved with a tiny snake. Hermione Granger also used one of its stalls to brew Polyjuice Potion in her second year.
• The Prefects' Bathroom: A luxurious bathroom on the fifth floor, reserved for school Prefects, Head Boy, Head Girl, and Quidditch captains. The password to enter is “Pine fresh.” The room features a large, swimming-pool-sized marble bath with hundreds of jewelled taps that dispense water with magical bubbles, foam, and scents. It was here that Harry Potter, with advice from Cedric Diggory and Moaning Myrtle, opened the Golden Egg underwater to decipher the clue for the Second Task of the Triwizard Tournament.
• Sixth-Floor Boys' Lavatory: This washroom was the scene of a violent duel between Harry Potter and Draco Malfoy in their sixth year. The confrontation ended when Harry used the Sectumsempra curse on Malfoy, nearly killing him. Moaning Myrtle often visited this washroom and witnessed the event, later helping Professor Snape find the two students. Harry also hid his copy of Advanced Potion-Making, owned by the Half-Blood Prince, in this location.
• Ministry of Magic Public Toilets: An underground public lavatory in Whitehall, London, which serves as a secret entrance to the Ministry of Magic. To enter, individuals must stand in a toilet and flush themselves, which transports them into a fireplace in the Ministry's Atrium. Harry, Ron, and Hermione used this entrance when they infiltrated the Ministry using Polyjuice Potion.

• On the Pottermore website, J.K. Rowling explained that before adopting Muggle plumbing in the eighteenth century, wizards and witches would simply relieve themselves wherever they stood and vanish the evidence with a charm. The introduction of plumbing at Hogwarts was contentious, but it inadvertently helped hide the entrance to the Chamber of Secrets, as Corvinus Gaunt incorporated it into the new pipework (Pottermore).
• In the film adaptations, the washrooms are often given a grander and more gothic architectural style. The Prefects' Bathroom, in particular, is depicted as a vast, cavernous chamber with a stained-glass window of a mermaid (film).