If you drink untreated water — and you shouldn’t — this is what you’re drinking

In 1854, a London anesthesiologist and amateur sleuth made a history-changing discovery about the link between contaminated water and human disease.

Several years before Louis Pasteur’s groundbreaking experiments that established what came to be called germ theory, Dr. John Snow thought he’d figured out why there were so many cholera cases in a central London neighborhood now known as Soho. The prevailing belief at the time was that cholera was caused by miasma — bad air.

Snow had another idea. He persuaded civic officials to remove the handle from the Broad Street pump, a water source for the neighboring businesses and residents. And fairly quickly, the cholera cases stopped.

Over a century and a half later, it appears some in modern society want the Broad Street pump handle back.

Just as some people extoll the so-called benefits of unpasteurized milk, a segment of the bottled water market is now embracing the idea of “raw” water. The argument: It tastes better. It’s more natural. It doesn’t contain additives like fluoride, which is often added to municipal water supplies to combat tooth decay.

But while the notion of crystal clear water bubbling up from a pristine spring sounds enticing, in reality there can be risks.

“When water is untreated, there is more uncertainty regarding what’s in it — and it may contain harmful germs,” explained Vincent Hill, chief of the Centers for Disease Control and Prevention’s waterborne disease prevention branch.

Think of them as nature’s additives. While these bugs — things like Cryptosporidium, Giardia, Shigella, and E. coli — can look lovely when captured by an electron micrograph, what they can do to your gastric tract definitely isn’t.

Take a glimpse.