Bathrooms

• Type: Utility Room
• Location: Various, notably Hogwarts School of Witchcraft and Wizardry, the Ministry of Magic, and wizarding homes.
• Owner/Residents: Varies by location; the ghost Moaning Myrtle famously haunts several bathrooms at Hogwarts.
• Key Features: May contain magical plumbing, secret entrances, or be home to magical beings.

Bathrooms in the Wizarding World serve the same fundamental purpose as their Muggle counterparts but are often imbued with magic or play a role in significant magical events. While most wizarding homes, such as The Burrow, have functional, ordinary bathrooms, institutions like Hogwarts feature bathrooms with unique properties. The history of bathrooms at Hogwarts is particularly noteworthy. Before the eighteenth century, wizards and witches simply relieved themselves wherever they stood and used a simple charm to vanish the evidence. When Muggle plumbing was introduced to the castle, the descendant of Salazar Slytherin, Corvinus Gaunt, was forced to conceal the entrance to the Chamber of Secrets within the plumbing of a newly constructed girls' bathroom (Pottermore). The bathrooms at Hogwarts range from the dreary and out-of-order to the exceptionally opulent, such as the Prefects' Bathroom, which features a swimming pool-sized tub with an array of magical taps.

Bathrooms serve as the backdrop for several pivotal moments in the series, often functioning as places of secrecy, conflict, or discovery.

• First-Year Troll Attack: Hermione Granger is attacked by a Mountain Troll in a girls' bathroom and is rescued by Harry Potter and Ron Weasley, an event which solidifies their friendship (PS).
• Polyjuice Potion Brewing: Hermione Granger secretly brews the complex Polyjuice Potion over several weeks in Moaning Myrtle's out-of-order bathroom (CS).
• Chamber of Secrets Entrance: Harry Potter discovers that one of the copper taps in Moaning Myrtle's bathroom is the hidden entrance to the Chamber of Secrets, which opens only to the sound of Parseltongue (CS).
• The Golden Egg Clue: Following a tip from Cedric Diggory, Harry takes the Golden Egg from the Triwizard Tournament to the Prefects' Bathroom. Submerging the egg in water reveals the merpeople's song, the clue for the Second Task (GoF).
• Duel and Sectumsempra: Harry and Draco Malfoy engage in a fierce duel in a sixth-floor boys' bathroom, culminating in Harry severely injuring Malfoy with the Sectumsempra curse from the Half-Blood Prince's potion book (HBP).
• Infiltrating the Ministry of Magic: Harry, Ron, and Hermione use enchanted tokens to access a set of subterranean public toilets that serve as an employees' entrance to the Ministry of Magic. They enter the Ministry by flushing themselves down the toilets after taking Polyjuice Potion (DH).

• Girls' Bathroom (First Floor, Hogwarts): Commonly known as Moaning Myrtle's Bathroom, this facility is out-of-order and largely avoided by students. It is haunted by the ghost Moaning Myrtle, who was killed there by the Basilisk. The bathroom's sinks contain the hidden entrance to the Chamber of Secrets.
• Prefects' Bathroom (Fifth Floor, Hogwarts): An exclusive and luxurious bathroom reserved for school Prefects, the Head Boy, the Head Girl, and Quidditch captains. It is protected by the password “Pine fresh.” Its main feature is a massive, rectangular marble tub with numerous gold taps that dispense water infused with different magical bubbles, scents, and foams. It also features a large painting of a mermaid.
• Boys' Bathroom (Sixth Floor, Hogwarts): Another bathroom frequented by Moaning Myrtle, this location is where Harry followed Draco Malfoy and overheard him crying to the ghost. It became the site of their destructive duel.
• Ministry of Magic Public Toilets: A shabby-looking underground lavatory that functions as a secret entrance to the Ministry of Magic. Witches and wizards enter a toilet cubicle and flush themselves to be transported into the fireplaces of the Ministry's Atrium.

According to writing by J.K. Rowling, when Hogwarts adopted Muggle plumbing, the Gaunt family ensured the entrance to the Chamber of Secrets was incorporated into the new pipework, preserving its secrecy for centuries (Pottermore). In the film adaptation of Harry Potter and the Chamber of Secrets, the tap that opens the Chamber is distinguished from the others by a small, carved silver snake, visually foreshadowing its connection to Salazar Slytherin (film). The set for the Prefects' Bathroom in Harry Potter and the Goblet of Fire was one of the largest and most elaborate created for the Hogwarts interiors (film).