SPECIAL: Chamber of Secrets and the Plumbing of Hogwarts

Chamber of Secrets (Pottermore post)

Let’s face it—this is probably everyone’s least-favorite Pottermore post ever. So little about it makes sense. For contrast, this is my head-canon on what really happened vis a vis the Chamber entrance and plumbing at Hogwarts in general:

The four Founders did not simply rely on magic to do things like build Hogwarts because they did not understand the Muggle way of building; they understood Muggle methods perfectly well but improved upon these methods with their magic.

Wizards had had indoor bathrooms—both bathing rooms and water closets—for a long time when Hogwarts was founded. Wizards understood the physics of plumbing because they did not need to work as hard as Muggles to do things like acquiring food to eat and clothes to wear. This gave them the luxury of time to work out how to most efficiently dispose of human waste without magic. Thus, regardless of whether someone in a magical household can do spells (a young child, the Muggle spouse of a magical person, Muggle parents visiting an adult Muggle-born wizard, etc.) the waste-removal system works the same for everyone.

Thus was Hogwarts built from the start with a rather advanced plumbing system that Muggles would not develop for centuries. When Muggles eventually caught up, their systems were similar to those of wizards because some wizards took pity on them and shared this information. They could do so because a) they did not reveal that they were wizards; b) they did not reveal the existence of the magical world; and c) the physics of plumbing involve no magic.

The Founders only relied on magic to build the castle and the plumbing system (with Slytherin showing a particular interest in the plumbing, to conceal that he was creating an entry to his Chamber of Secrets). The structure of the castle was not magical until after its completion; then spells were placed on staircases to make them move, or on the plumbing to keep it clog-free and to heat water for washing.

It is notable that the architectural style of the castle is similar to other structures built at the same time by Muggles. Wizards routinely use magic to alter parts of Muggle dwellings, such as fireplaces and toilets; fireplaces are magically linked to the Floo network, and toilets in a Muggle public bathroom near the Ministry are used by wizards to enter the Ministry. The fireplaces and toilets in question are also still usable as normal fireplaces and toilets and the physics governing their function is the same as for fireplaces and toilets in unaltered Muggle-built structures.

There you go! No need to think about wizards defecating in the corridors and then using vanishing charms to dispose of their waste. No need to wonder if every child arriving at Hogwarts was already supposed to know how to do vanishing charms (even though they’d just bought their wands and had had no magical education yet, plus vanishing charms seem to be rather advanced fifth-year Transfiguration work). No need to wonder why Dumbledore didn’t just do this when he was wandering the castle at night, needing to relieve himself, and then stumbled on a version of the Room of Requirement filled with chamber pots.