50 free Plumbing trivia questions with answers — technology quiz, new questions added Aug 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 50 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 02Standardised earthenware pipes with sealed flanges appeared by 2700 BC in which civilisation?
The Indus Valley
Copper piping followed in Egypt by 2400 BC, linking the Pyramid of Sahure to its temple complex.
Q 03Rome's first aqueduct, the Aqua Appia, was built in which year?
312 BC
By the third century AD the city had eleven aqueducts, feeding mostly its public baths, all moving water by gravity alone.
Q 04The Cloaca Maxima, one of the world's oldest sewers, served which ancient city?
Rome
It began as an open canal to drain marshes, is named for the goddess Cloacina, and parts of it are still in use today.
Q 05The Roman hypocaust was an early form of what?
Underfloor central heating
Hot air from a furnace circulated beneath raised floors and up through wall pipes, a forerunner of modern central heating.
Q 06Sir John Harington, who described a flush toilet in 1596, installed one for which royal godmother?
Elizabeth I
The device went into Richmond Palace, and his book about it was called A New Discourse of a Stale Subject.
Q 07The S-trap, which keeps sewer gas out of buildings, was patented in 1775 by whom?
Alexander Cumming
The Scottish mechanic's design was the crucial step toward the modern flush toilet; Bramah improved on it three years later.
Q 08Joseph Bramah, who patented the first practical flush toilet in 1778, is also famous for inventing what?
The hydraulic press
He was also a celebrated locksmith whose challenge lock went unpicked for 67 years.
Q 09Which of these is true of Thomas Crapper?
He patented the floating ballcock
The English plumber's fame was inflated by a 1969 satirical biography, and the word crap is Middle English, older than his career.
Q 10What is the purpose of the U-shaped trap under a sink?
To hold water that blocks sewer gases
The standing water in the bend forms a seal; the same idea protects drains in oil refineries from escaping fumes.
Q 11In a drain-waste-vent system, what is the job of the vent pipe that runs up through the roof?
To stop a vacuum forming in the pipes
Without venting, draining water can siphon the traps dry and let sewer gas into the house.
Q 12The ballcock in a toilet cistern gets its name from what?
The ball-shaped float on its lever
A lever connects the hollow float to the fill valve, shutting off the water when the tank is full and preventing overflow.
Q 13The banging noise in pipes when a tap is shut off suddenly is known as what?
Water hammer
Q 21The Washlet, the electronic bidet seat found across Japan, is made by which company?
Toto
It launched in June 1980 and has sold more than 70 million units.
Q 22The word bidet originally referred to what in French?
A small horse
The fixture took the name because of the straddling position used to sit on it.
Q 23The 1858 Great Stink, which drove Parliament to act on sewage, was caused by the smell of which river?
The Thames
A hot summer cooked the untreated waste on the riverbanks until the stench reached the Commons.
Which engineer built London's main drainage system in response to the Great Stink?
It is a pressure surge from moving water stopping abruptly, and it can be cured with an arrestor that cushions the shock.
Q 14PEX, the flexible red and blue tubing used in home water lines, is short for what?
Cross-linked polyethylene
The cross-linking greatly improves impact strength and resistance to stress cracking compared with ordinary polyethylene.
Q 15White plumber's tape wrapped around threaded joints is made of which material?
PTFE
The same fluoropolymer is sold under the Teflon name; the US military spec calls for at least 99 percent purity.
Q 16The Stillson wrench, the classic pipe wrench, was created by a mechanic at which Massachusetts firm?
Walworth
Daniel Stillson licensed his design to many manufacturers, and the patent has long since expired.
Q 17The plumbing plunger was invented in 1874 by John Hawley, a New Yorker in what line of work?
Confectioner
The flattened rim was added two years later; the tool is also called a force cup or plumber's friend.
Q 18The 1933 Roto-Rooter rig was built from wagon wheels, a steel cable and the motor from what?
A washing machine
Samuel Blanc of Des Moines, Iowa cobbled it together after clearing a blocked sewer at his son's apartment.
Q 19The 'septic' in septic tank refers to what?
The anaerobic bacteria inside it
The tank provides only primary treatment; the liquid then flows to a drain field for more.
Q 20The Kohler company made its first bathtub in 1883 by applying enamel to what?
A cast-iron horse trough
The Wisconsin firm had been founded ten years earlier by Austrian immigrant John Michael Kohler.
Joseph Bazalgette
His 82 miles of intercepting sewers ended the city's cholera outbreaks and gave London the Victoria, Chelsea and Albert Embankments.
Q 25The 2017 Whitechapel fatberg found under London weighed about how much?
130 tonnes
It stretched more than 250 metres, was mostly wet wipes and cooking fat, and a chunk of it went on display at the Museum of London.
Q 26Fatbergs form when fat, oil and grease combine with what flushed item in particular?
Wet wipes
The so-called flushable wipes do not break down, and utilities have run campaigns to keep them out of toilets.
Q 27The Tremont House in Boston, opened in 1829, is best remembered as the first hotel with what?
Indoor plumbing and running water
It had eight water closets on the ground floor and basement bathrooms with cold running water, plus free soap in every room.
Q 28The 2014 water crisis in Flint, Michigan began when the city switched its supply from Lake Huron to what?
A local river
Officials failed to add corrosion inhibitors, so lead leached from old pipes and exposed about 100,000 people.
Q 29Hard water, which leaves limescale, is rich in dissolved compounds of which two elements?
Calcium and magnesium
A water softener swaps those ions for sodium using an ion-exchange resin.
Q 30The US Energy Policy Act of 1992 capped new toilets at how many gallons per flush?
1.6
The low-flow mandate was widely mocked at first because early models often needed a second flush.