Plumbing Trivia
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97 free Plumbing trivia questions with answers — technology quiz, new questions added Oct 2026.
42 free Plumbing trivia questions with answers. Plumbing is one of the oldest trades and one of the least celebrated, so this quiz gives it its due. It covers the Roman lead pipes that gave the profession its name, the Indus Valley drains that predate them, the Elizabethan courtier who built a flush toilet for the queen, the Scottish clockmaker who patented the S-trap, and the London engineer whose sewers ended cholera in the capital. It also asks how a P-trap works, what PEX and PVC are, why plumber's tape is used, who invented the plunger and the pipe wrench, and what a 130-ton fatberg is made of. Easy questions suit anyone who has ever fixed a running toilet; the harder ones are for tradespeople, apprentices and history buffs, with a few detours into Mario, Joe the Plumber and Japan's Washlet. It works for an apprentice class, a trade-show booth or a pub round for the building crew. Every answer has been checked against Wikipedia and reference sources, and each question shows an explanation and its citation once you answer.
30 of 97 questions with answers and explanations. Play the quiz
Q 01The word plumber comes from the Latin plumbum, which means what?
Lead
The first effective pipes in the Roman era were made of lead, and the metal's chemical symbol Pb comes from the same root.
Q 02The Cloaca Maxima, ancient Rome's great sewer, still empties into which river?
The Tiber
The Tiber still takes the outfall of the Cloaca Maxima, which began in the sixth century BC as an open channel draining the Forum valley and was only roofed over with a stone vault centuries later.
Q 03The Roman hypocaust was an early form of what?
Underfloor central heating
Underfloor central heating is what a hypocaust provided: a furnace sent hot air beneath floors raised on stacks of tiles and up flues inside the walls, so the walls gave off warmth too.
Q 04Sir John Harington, who described a flush toilet in 1596, installed one for which royal godmother?
Elizabeth I
Elizabeth I had her godson's flush toilet installed at Richmond Palace; his 1596 book about it, The Metamorphosis of Ajax, punned on 'a jakes', slang for a privy, and got him banished from court.
Q 05Who patented the S-trap, the bend beneath sinks and toilets, in 1775?
Alexander Cumming
Alexander Cumming, a Scottish watchmaker, patented the S-trap in 1775, the key step toward the modern flush toilet; Bramah improved the mechanism three years later.
Q 06Joseph Bramah, who patented an improved flush toilet in 1778, is also famous for inventing what?
The hydraulic press
The hydraulic press, which Joseph Bramah patented in 1795, multiplies force through fluid pressure; he also offered 200 guineas to anyone who could pick his lock, a prize nobody claimed until 1851.
Q 07Which Victorian plumber, wrongly credited with inventing the flush toilet, still has his name on manhole covers around London?
Thomas Crapper
Thomas Crapper ran a successful London plumbing firm and held nine patents, none of them for the flush toilet; the legend grew out of Flushed with Pride, a tongue-in-cheek 1969 biography full of puns.
Q 08What is the purpose of the U-shaped trap under a sink?
To hold water that blocks sewer gases
To hold water that blocks sewer gases: the bend stays full after every use, and if that seal evaporates in a rarely used drain, the smell of the sewer comes straight up into the room.
Q 09What is a plumbing vent stack on the roof for?
To stop a vacuum forming in the pipes
To stop a vacuum forming in the pipes, the vent lets air in behind each rush of draining water; when a vent is blocked, the drains pull air in through the fixtures instead and start to gurgle.
Q 10When the float in a toilet cistern rises to its set level, what does the ballcock do?
Shuts off the incoming water
Shuts off the incoming water: the rising float lifts a lever that closes the fill valve, and when a flush drops the level the float falls and opens it again, so the cistern refills itself.
Q 11The banging noise in pipes when a tap is shut off suddenly is known as what?
Water hammer
Water hammer is the shock wave made when moving water is stopped dead; it can be strong enough to rupture pipes, and the hydraulic ram pump puts the same surge to work, lifting water with no outside power.
Q 12PEX, the flexible red and blue tubing used in home water lines, is short for what?
Cross-linked polyethylene
PEX stands for cross-linked polyethylene; the cross-linking greatly improves impact strength and resistance to stress cracking compared with ordinary polyethylene.
Q 13White plumber's tape wrapped around threaded joints is made of which material?
PTFE
Q 21The 1858 Great Stink, which drove Parliament to act on sewage, was caused by the smell of which river?
The Thames
The hot summer of 1858 cooked untreated sewage on the Thames's banks until the stench reached the Commons, whose curtains were soaked in chloride of lime.
Q 22Which Victorian engineer built the great intercepting sewers that answered the Great Stink of 1858?
Joseph Bazalgette
Joseph Bazalgette, chief engineer of the Metropolitan Board of Works, built a network of intercepting sewers that helped end the capital's cholera epidemics, and laid out the Victoria, Albert and Chelsea Embankments.
Q 23Which institution displayed a piece of the 2017 Whitechapel fatberg?
Museum of London
Thread seal tape is PTFE (polytetrafluoroethylene), the fluoropolymer sold under the Teflon name; it lubricates the threads and fills gaps to seal the joint.
Q 14Which plumber's tool, with serrated jaws that tighten as it is turned, is still called a Stillson?
Pipe wrench
The pipe wrench was devised by Daniel Stillson, a mechanic at the Walworth company in Massachusetts; its hard teeth bite into the softer metal of a round pipe, which gives the grip to turn it.
Q 15Which drain-clearing tool is also known as a plumber's friend or a plumber's helper?
Plunger
The plunger works by sealing its rubber cup over the drain, so each push and pull drives the water in the pipe against the clog; lift it far enough to break the seal and the force is lost.
Q 16The first Roto-Rooter drain cleaner, built in 1933, was powered by the motor from what?
A washing machine
Samuel Blanc of Des Moines, Iowa built it from a washing machine motor and a steel cable tipped with a blade, after clearing tree roots from the sewer at his son's apartment; his wife Lettie named it the Roto-Rooter.
Q 17The 'septic' in septic tank refers to what?
The anaerobic bacteria inside it
The anaerobic bacteria inside it give the septic tank its name: they rot the solids without oxygen, and 'septic' goes back to a Greek word for putrefying, the same root as antiseptic.
Q 18Which Wisconsin bathroom brand made its first bathtub in 1883 by enamelling a cast-iron horse trough?
Kohler
Kohler was a Wisconsin foundry making farm implements until John Michael Kohler enamelled a cast-iron horse trough in 1883 and sold it as a bathtub; plumbing has been its main business ever since.
Q 19The Washlet, the electronic toilet seat with a built-in washing spray found across Japan, is made by which company?
Toto
Toto, the Kitakyushu-based sanitaryware maker, launched the Washlet in June 1980, and its 1982 'even bottoms want to be washed' television campaign made it a Japanese household name.
Q 20Which bathroom fixture takes its name from an old French word for a pony?
The bidet
The bidet borrows the French word for a small horse because the user sits astride it as if riding; English had the word for a pony for well over a century before it meant a bathroom fitting.
The Museum of London showed an air-dried chunk of the sewer blockage in 2018; inside its sealed case the lump changed colour and hatched flies in front of visitors.
Q 24Fatbergs form when fat, oil and grease combine with what flushed item in particular?
Wet wipes
Wet wipes, even those sold as flushable, do not break apart in water the way toilet paper does; they snag in the sewer and bind with congealed fat and grease into a rock-like mass.
Q 25The Tremont House, which in 1829 became the first hotel with indoor plumbing, stood in which American city?
Boston
Boston's Tremont House raised water by steam pump to a tank on its roof, which fed eight ground-floor water closets and the hotel's bathrooms by gravity; every room also came with free soap.
Q 26The 2014 water crisis in Flint, Michigan began when the city switched its supply from Lake Huron to what?
A local river
A local river, the Flint, replaced treated Detroit water in April 2014; officials added no corrosion inhibitors, so its harsher water corroded the city's ageing pipes and poisoned the tap water.
Q 27Hard water, which leaves limescale, is rich in dissolved compounds of which two elements?
Calcium and magnesium
Hard water carries dissolved calcium and magnesium salts, which precipitate as limescale when heated; a water softener swaps those ions for sodium using an ion-exchange resin.
Q 28The US Energy Policy Act of 1992 capped new toilets at how many gallons per flush?
1.6
1.6 gallons a flush became the limit for new toilets from 1994, less than half the 3.5 gallons then typical; the first low-flow models performed poorly, and it took redesigned bowls to make the saving work.
Q 29The dual-flush toilet was first put into practical production in the early 1980s by a company in which country?
Australia
Australia's Caroma built the first practical two-button cistern, with a full flush of 11 litres and a half flush of 5.5; the idea caught on so widely that new buildings there are often required by law to have one.
Q 30John Hammes invented the garbage disposal in 1927 and later founded which company to sell it?
InSinkErator
Hammes, an architect in Racine, Wisconsin, founded InSinkErator with his sons in 1938; the company then spent years persuading American cities to lift their bans on putting food waste down the drain.