High-profile Bay Area denizens are skipping tap water in favor of drinking unfiltered, untreated, and expensive “raw” water that comes straight out of the ground, Nellie Bowles reports for The New York Times. Proponents claim that raw water’s health benefits include naturally occurring minerals and microbes. But the reality for any inadequately treated water from the tap or a spring is that those minerals can sometimes include arsenic, and those microbes can be deadly.

The trend is borne of distrust for the public water supply, Bowles writes — including the disinfection processes the water undergoes, the fluoride that’s sometimes added to it, and the lead pipes that might carry it. But adding fluoride prevents tooth decay. (“There is no scientific evidence that fluoride is a mind-control drug, but plenty to show that it aids dental health,” Bowles writes.) And disinfecting water is key for preventing the spread of dangerous viruses, bacteria, and parasites.

In fact, civilizations have been trying to clean up their water supplies for millennia. As early as 1500 BCE, the ancient Egyptians are said to have clarified cloudy water using techniques similar to ones we use today, according to a report from the Environmental Protection Agency. “Sanskrit and Greek writings recommended water treatment methods such as filtering through charcoal, exposing to sunlight, boiling, and straining,” the report says.

Apparently people are rushing to get "raw water." Just wait till they get "raw cholera". https://t.co/rorvv3xOFy — Sarah Parcak (@indyfromspace) January 1, 2018

At the turn of the 20th century, public water utilities in the US started focusing on removing dangerous, disease-causing microbes from water — turning to chlorine disinfection for the first time in 1908. The disinfection effort has drastically reduced cases of deadly diarrheal diseases like typhoid and cholera that spread via contaminated water, which the Centers for Disease Control and Prevention calls “one of the greatest public health achievements of the 20th century.”

It’s not just city water supplies that need to be treated. Water that springs up in the apparently pristine wilderness can also make you sick — in part because animals poop. “While the water flowing in the streams and rivers of the backcountry may look pure, it can still be contaminated with bacteria, viruses, parasites, and other contaminants,” the CDC warns. That’s why the agency recommends that backpackers boil water for between one and three minutes. If that’s not possible, the next best option is both chemically treating and filtering the water.

Water that springs up in the apparently pristine wilderness can also make you sick

Groundwater wells — the ultimate in off-the-grid water that roughly 15 million households in the US rely on — also need to be routinely tested for safety. Chemicals like arsenic, metals like uranium, or contaminants from agricultural activities like nitrates can leach into the groundwater that supplies both wells and springs. Even rainwater — which is a great for your garden — is less safe for drinking unless it’s been treated, the CDC says. Animal feces, chemicals in air pollution or in roofing materials and gutters, and insect larvae can all swim around in rain barrels.

Now, it’s true that there are problems with public drinking water: the lead poisoning of Flint, Michigan’s children is a devastating example that drew attention to the alarming extent of lead pipes in the US. Scientists have detected low levels of pharmaceuticals in water supplies, although it’s not clear exactly what that means for public health. And inadequately treated water may sometimes contain risky levels of arsenic and hexavalent chromium, the potentially cancer-causing chemical that Erin Brockovich made famous.

But the answer isn’t, as the New York Times’ Kendra Pierre-Louis tweets, for the wealthy, worried well to just opt out of the public water supply. Nor is it for them leap into the arms of another poorly-regulated, money-making scheme that could make them sick (see: workout supplements). Instead the answer is to continue to push public officials, water utilities, and industry to ensure that our water infrastructure supplies water that is safe for everyone — and to insist that these sectors face the consequences when they fail.