Plumbing Trivia: Who Invented the Toilet?

Plumbing is one of those things nobody thinks about until it stops working. It also has a surprisingly good backstory. Here are ten questions people search all the time, with answers from museums, manufacturers and the people who write the codes.

Real OX Plumbing job: New PEX water lines run through opened walls during a repipe.

1. Who invented the toilet?

Not one person. Early drains and waste systems go back thousands of years; London's Science Museum points to a drainage system about 5,000 years old in Scotland's Orkney Islands. But the flush toilet as we know it has three names attached:

Sir John Harington, 1596. Queen Elizabeth I's godson described a flushing device in a book called The Metamorphosis of Ajax, and later installed a working model for the Queen at Richmond Palace. According to the Science Museum, it used about 7.5 gallons of water and didn't catch on.
Alexander Cumming, 1775. He was granted the first English patent for a flushing toilet. His big idea was a built-in S-shaped pipe that held water and kept sewer smells from coming back up. Every toilet and sink drain still uses that idea today.
Joseph Bramah, 1778. A locksmith and inventor who improved Cumming's design with a hinged valve.

Even so, chamber pots and cesspits stayed the most common setup until the late 1800s.

2. Did Thomas Crapper invent the toilet?

No. Flush toilets were around for centuries before him. Thomas Crapper was a real English plumber, and the Smithsonian credits him with something else: the bathroom fixtures showroom. The Science Museum says he also adapted Cumming's S-pipe into the U-bend.

And the word "crap"? It was slang before Crapper went into business. The nickname "crapper" for a toilet may come from him, though: the Smithsonian notes that American soldiers in England may have seen toilet tanks stamped "T Crapper" and brought the word home.

3. Who invented toilet paper?

The man usually credited is J. C. Gayetty of New York, who sold "medicated paper for the water-closet." The Library of Congress holds one of his ads, which told buyers to look for his name watermarked on every sheet, and he was advertising in Chicago newspapers by 1859.

4. How does a toilet work?

A regular toilet doesn't push the waste out. It siphons it out. Kohler explains it like this:

At rest, the water in the bowl and the water in the curved trapway behind it sit at the same pressure, so a little water stays in the bowl.
When you press the handle, the flapper in the tank opens and a rush of water fills the bowl and the trapway, pushing the air out. That change in pressure starts a siphon, which pulls everything down the drain.
When enough water leaves the tank, the flapper closes. Air gets back into the trapway and the siphon stops.
As the tank level drops, a float on the fill valve drops too, which turns the water back on until the tank is full again.

That's why a worn flapper means a running toilet: water keeps sneaking from the tank into the bowl.

5. What is a P-trap?

It's the curved pipe under your sink (people often search it as "pee trap"). InterNACHI, the home inspectors' association, defines a trap as a fitting that holds a water seal to keep sewer gas out of the house. The seal is usually about 2 inches deep. A P-trap is the shape: water goes down, curves, and leaves sideways.

It's a direct descendant of Cumming's 1775 S-pipe. But a true S-shaped trap can siphon itself dry ("a perfect siphon," InterNACHI says), and a dry trap lets sewer gas in. That's why modern drains use the P shape plus a vent. If a sink you rarely use starts to smell, the trap may simply have dried out: run the water for a few seconds.

6. Why does my toilet gurgle?

Drains need air to flow smoothly, the same way a juice carton glugs if you pour it without a vent hole. Your plumbing gets that air through vent pipes that run up through the roof. InterNACHI says venting is what prevents trap seals from being lost and flow from slowing down.

When a toilet gurgles, or a tub gurgles when you flush, it usually means:

A partial clog in the drain or main line, so air is getting pulled through the water instead of flowing freely, or
A blocked or missing vent, so draining water pulls air from the nearest trap

One gurgle now and then is normal. Gurgling that keeps happening, or shows up in more than one fixture, is worth a look before it becomes a backup. More in can a shower and toilet share a drain? and signs of sewer line problems.

7. How long do pipes last?

InterNACHI's life expectancy chart for homes gives these guidelines:

Copper water lines: 50 to 70 years
PEX: 40 years
Cast-iron drain pipe: 60 years above ground, 50 to 60 below
ABS and PVC drain pipe: 50 to 80 years
Faucets: 15 to 20 years
Toilets: 100+ years for the toilet itself, but only about 5 years for the parts inside the tank

InterNACHI is clear that these are guidelines, not guarantees: water, installation and maintenance all change the number. In the East Valley, hard water is the big one. If a house has had several leaks in old pipe, see repiping.

8. Why is my cold water hot?

If you live in the Valley, this one's for you. The City of Mesa's 2025 water quality report answers it directly: groundwater in some areas, especially east Mesa, is naturally warm, and spring and summer heat make it warmer still. So in summer, the "cold" tap running warm is often normal.

If it's your hot water that isn't hot, that's a different problem; see signs your water heater needs replacing.

9. Why is it called a plumber?

Because of lead. Merriam-Webster traces "plumber" to the Latin plumbum, meaning lead, and the first meaning of the word was "a dealer or worker in lead." Lead's chemical symbol is still Pb for the same reason.

10. When did the U.S. stop using lead pipes?

The 1986 amendments to the Safe Drinking Water Act banned lead pipe, solder and flux in plumbing that carries drinking water, starting in June 1986. Back then "lead-free" still allowed up to 8% lead in pipes; in 2011 Congress lowered the limit to a weighted average of 0.25%, according to the EPA. If your home was built before 1986 and you're curious what's in your pipes, a plumber can check.

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Plumbing Trivia: Who Invented the Toilet? And 9 More Questions, Answered