Silicon Valley is developing an obsession with untreated, unfiltered water.

"Raw" water can spread bacteria and diseases including cholera, E. coli, Hepatitis A, and Giardia.

People make illogical decisions and buy into absurd trends because of a reliance on emotions and their personal experiences over historical and scientific facts.

Silicon Valley is no stranger to bizarre trends.

The latest: unfiltered, untreated water. Sold as "raw" or "live" water, fans say that the beverage has health benefits that tap or traditional bottled water lacks.

There's a lot that's wrong with this. First, there's no scientific evidence that untreated water has additional health benefits. In fact, there's a lot of evidence that water that isn't properly treated is extremely dangerous.

"Almost everything conceivable that can make you sick can be found in water," food safety expert Bill Marler told Business Insider.

Unfiltered, untreated water, even from the cleanest streams, can contain animal feces, spreading Giardia, which brings on symptoms such as vomiting and diarrhea and results in roughly 4,600 hospitalizations a year. Hepatitis A, which resulted in 20 deaths in a California outbreak in 2017, can be spread through water if it isn't treated. E. coli and cholera can also be transmitted via untreated water.

The reason these infections aren't killing Americans constantly is because of scientific advances — and safety regulations — that have been made over the last century. Obsession with the dangerous beverage in certain circles reveals both an unscientific self-absorption and a lack of historical understanding.

Because filtered, treated water has become the norm, Marler says, most people don't realize how dangerous s0-called "raw water" can be.

"The diseases that killed our great-grandparents were completely forgotten about," he said.

Most Americans don't personally know anyone who died of Hepatitis A or cholera, thanks to advances in technology and more stringent safety standards. As a result, they had a hard time realizing the risks involved in consuming untreated water.

"It's fine till some 10-year-old girl dies a horrible death from cholera in Montecito, California," Marler said.

In other words, those who forget history are doomed to repeat it.

In fact, the lack of clean water is still an issue in the modern world — including parts of the US. Roughly 200 million Americans said in a recent survey by the water advocacy brand Bluewater that they worry about contaminants in their drinking water.

It's a problem that persists far beyond untreated water.

"Similar to Bodega (which seeks to replace independent corner stores) and the now-defunct Juicero (which sold $400 juicers), 'raw water' startups may be trying to solve a problem that doesn't exist — at least in Silicon Valley," reported Business Insider's Leanna Garfield.

According to Marler, the raw-water trend is similar to people's obsession with raw milk or opposition to vaccines. While they lack scientific evidence, they're convinced that they are correct, in part because they have failed to see the repercussions of life without scientific advances.

Spring water — without any modern filtering systems — appeals to people's emotional idea of purity and health. It only takes talking to a scientist or reading a history book to see that consuming unfiltered water has lead to countless deaths over the centuries.

"You can't stop consenting adults from being stupid," Marler said. "But we should at least try."