We as a society had to go through a lot of epic fails before we created today's bathroom. For centuries, people in big cities got their cooking and washing water from rivers or wells, limiting their consumption to pretty much what they could carry. They dumped their waste into brick-lined cesspits that would be emptied by the night soil men, who sometimes sold it as fertilizer. Liquid waste, on the other hand, would get thrown into gutters in the middle of the road.

The Guardian pointed out that in 1854, in the middle of a cholera epidemic in London, Dr John Snow (not to be confused with Jon Snow) mapped where victims died and found that the deaths seemed concentrated around one of those pumps, at 37 Broad Street. Interestingly, when he had the handle removed from the pump, the cholera epidemic stopped immediately. Thus, the first verifiable connection between human waste and disease was made.

After people realized that excrement + drinking water = death, parliament passed the Metropolitan Water Act to “make provision for securing the supply to the metropolis of pure and wholesome water”. As a result, pipes delivering water directly to homes started replacing public pumps.

The next trivial addition to this convenience was the toilet. Believe it or not, the invention had been around for a while. However, it was pretty useless without a water supply.

As it became really easy to just wash the poop away, there soon was so much fecal effluence, it started overflowing from the cesspits. The result of this design fail? Even more cholera and other diseases.

Architects, engineers and homeowners of the late 19th century didn't know what to do. A lot of people had washstands in their bedrooms, so at first they just stuck sinks and taps into them, and put the toilet into whatever closet in the hall or space under the stairs that they could find, hence the “water closet.” However, it didn’t make a lot of sense to run plumbing to every bedroom when it was cheaper to bring it all to one place, and the idea of the bathroom was born.

Since the early adopters, then as now, were the rich with a few rooms to spare, they were often lavish, with all the fixtures encased in wood like the commodes they replaced. But when the bathroom became mainstream and accessible to all classes, it got smaller (cheaper to build). Around 1910, the bathroom started looking pretty much the same way it does now.