Not even close.
Dear Word Detective: “The Perfect Summer” by Juliet Nicolson, page 80, reads: “Lady Louisa Anson, an intimidating guest at Viceregal Lodge in (Victorian) Ireland, was so rude to the Viceroy’s children they stole the name card from her bedroom door and slid it into the holder on the door of the water closet. The lady was not amused when the maid persistently misdelivered her morning tea. The story spread and from then on people needing a discreet reason to excuse themselves would announce they were off to visit Lady Loo or as it became known simply ‘The Loo’.” Could this be true? — Roger Baker.
Absolutely not. I’ve removed a few of the question marks you appended to your query for emphasis, but your incredulity is richly justified. That story is nonsense. I must say, however, that it is curiously attractive because it exhibits several of the key elements of a successful urban legend. There’s the presence of the aristocracy, always a winner. More importantly, the snobby rich person gets her comeuppance at the hands of the downtrodden (albeit also rich) children she has wronged. And the whole tale centers on the socially taboo subject of toilets. No wonder the author was suckered by that story.
That looks like an interesting book, by the way. It’s a portrait of the summer of 1911, three years before the start of World War I, focusing on the upper crust of British society, and written by the granddaughter of Vita Sackville-West and Harold Nicolson. But did guests at a Viceroy’s mansion really have their rooms marked by little name cards on the door? How tacky. I wonder if they also wore those “Hi, My name is” things at dinner.
“Loo” is, of course, slang, primarily British, for the toilet, restroom or bathroom (or whatever your favorite euphemism might be). The origin of “loo” has been hotly, and often quite creatively, debated since the word first appeared. One popular theory suggests that servants in the 17th and 18th century, emptying chamberpots out the window, warned passersby in the street below with the shout “Gardez l’eau!” (French for “Watch out for the water!”), which was pronounced “gardy loo” in Britain and later shortened to “loo.”
This story, however, like many of the more colorful origins proposed, runs aground on the fact that “loo” first appeared in print relatively recently, in 1922 (in the form of a joke in “Ulysses” by James Joyce: “O yes, mon loup. How much cost? Waterloo. Watercloset.”). The 1922 vintage of “loo” also casts doubt on Nicolson’s account, since it is set no later than 1911.
There are two theories, however, that should be considered more likely. The French euphemism “lieux” (pronounced “loo,” from “lieux d’aisance,” meaning “places of comfort” or “comfort stations”) might well have been picked up by British soldiers in France during World War I (1914-17). The period between the war and the first appearance of “loo” in print would be about right for armed services slang to percolate into general usage.
On the other hand, James Joyce may, in that quote from “Ulysses,” have been onto the actual origin of “loo.” It may simply be a joke based on the use of “Waterloo” (as in “Battle of Waterloo”) as a punning take on “water closet.” Such a linkage would make “loo” similar to British rhyming slang, where a nonsense phrase rhyming with the “real” word (“plates of meat” for “feet”) is abbreviated and obscured still further by dropping the bit that actually rhymes (leaving us with the mysterious “plates” as slang for “feet”). “Water closet” thus, in this theory, became “Waterloo,” and then just “loo.”