A New York Times story in December introduced a new health buzzword to the masses: raw water, or water that hasn’t been treated, filtered or processed in any way.

While the beverage isn’t widespread yet, a number of untreated water startups have cropped up in states ranging from California to Maine, according to the Times. They’re attracting those with misgivings about tap water treatment processes and additives, as well as people who want to preserve the natural substances found in virgin water.

But is the stuff even safe?

The water system in the U.S. isn’t perfect — there are aging pipes and infrastructure issues, for example, and lead contamination like that in Flint, Mich. — but it has greatly improved public health over the past century. After the U.S. introduced filtration, chlorination and sanitation practices for public drinking water, the burden of water-borne illnesses such as cholera and typhoid fever plummeted almost to zero, says Kellogg Schwab, a professor of water and public health at Johns Hopkins University’s Bloomberg School of Public Health. “It was truly instrumental in improving public health in the United States,” Schwab says. “Having a central treatment process of our drinking water and then distributing it out to the individual homes and businesses is a tremendous asset that we, as a country, take for granted.”

Drinking untreated water, and the pathogens that can lurk within it, could expose Americans to disease outbreaks once again, says Vince Hill, chief of the CDC’s Waterborne Disease Prevention Branch. “When water isn’t treated, it can contain chemicals and germs that can make us sick or cause disease outbreaks,” he says. “Anything you can think of can be in untreated water, really,” ranging from agricultural runoff and naturally occurring chemicals to bacteria and viruses.

And while community tap water is treated to remove 91 different contaminants, there’s little data showing what’s in raw water. “That’s the part that is concerning, because there are many sources of water contamination that can affect spring water,” Hill says.

As for concerns about fluoride — a chemical added to community water supplies to help prevent tooth decay — Vincent Casey, a senior water sanitation and hygiene manager at clean water nonprofit WaterAid, says it’s not harmful at the levels found in drinking water, even though it is hazardous at high concentrations. (Due to its potential health consequences, some vocal opponents have called for an end to water fluoridation.)

“In low quantities, it is scientifically proven that it is beneficial to dental health,” Casey says. “If a water company or a utility is carrying out its treatment to the right standards, there shouldn’t be instances where these concentrations are going to hazardous levels at all.”

If you’re concerned about your tap water, Hill says, it’s better to invest in a home filtration or testing system than to turn to untreated water.

Casey agrees. “If you’ve got the luxury of a treated, piped water supply to your home available, it’s not really a good idea to drink untreated water,” he says. “There are obviously many people in the world who don’t have that luxury.”

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Write to Jamie Ducharme at jamie.ducharme@time.com.