This is 99% invisible. I'm Roman Mars.

Every time you go to the bathroom, you should thank Alexander coming.

We actually featured a whole story about him,

because Alexander coming was the first person to patent a flushable toilet.

He didn't invent the flush toilet, but he did connect it to an S-shaped pipe which uses water to stop sewer gas from coming up and

stinking up your home. And before Alexander coming, that used to happen a lot.

Whatever was underneath the toilet could come back up.

People didn't like bad smells,

but they also thought that bad smells carried disease.

That's how the flush came about. That's Chelsea how the Flush came about.

That's Chelsea Wald.

I'm the author of Pipe Dreams, The Urgent Global Quest to Transform the Toilet.

The Flush toilet took a while to catch on, but once it did, it became part of a system we still use today, which Chelsea calls the gold standard. Here's how it works.

Your poop once deposited into the toilet and you flush it down goes into a sewer system that runs under the city and there it combines with water and with everyone else's poop and anything anyone puts into their sinks and their toilets and their showers and their washing machines and their dishwashers flows through to a treatment plant and in the treatment plant

bacteria helped to clean up the sewage.

The treatment plant produces cleaned up wastewater, which is usually returned to our water supply,

and it filters out all the solids.

The flush toilet, the sewer system, and the treatment plant

make up the gold standard in a lot of ways it's a really

good system. Toilet technology, the toilet systems that people's developed in

the 19th and early 20th century that we still use today fundamentally,

work very well at keeping our cities clean and keeping us healthy.

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