It was translated!

In much of the Spanish-speaking world, "Water Closet" (often abbreviated as 'W.C') is borrowed from English, and can mean the same as the American terms toilet (the actual porcelain fixture) or bathroom (the room which contains the porcelain fixture).

In Mexico I recently saw a sign advising patrons not to throw trash in the W.C., for instance.

So what you saw was a translation from "toilet" to the short version of the Anglicanism "water closet".

It was translated!

In much of the Spanish-speaking world, "Water Closet" (often abbreviated as 'W.C') is borrowed from English, and can mean the same as the American terms toilet (the actual porcelain fixture) or bathroom (the room which contains the porcelain fixture).

I took this photo in a public restroom in Madrid, for instance:

So what you saw was a translation from "toilet" to the short version of the Anglicanism "water closet".