Trendy diets and lifestyle choices come and go, and some of them are more extreme than others. There’s raw milk, raw foods, and foods that are free of just about everything. But the latest phenomenon has some experts alarmed. People are trading in their treated, clean water for raw, unfiltered water. Should you?

Throughout the world, we are very fortunate to have clean, filtered water to drink whenever we want. And maybe some of us have started to take it for granted. Thanks to the treatment process, water is safe for us to drink, and free of harmful bacteria and diseases spread via dirty water.

Nonetheless, unfiltered and unsterilized water is now selling at a high cost in San Francisco, California, much to the disbelief of Bill Marler, a food-safety advocate and lawyer.

In fact, in an interview with Business Insider, Marler reminds readers that “Almost everything conceivable that can make you sick can be found in water”, and that goes for everything from Giardia, Hepatitis A, E. coli and cholera.

Raw, unfiltered water is sourced from natural springs and is advertised in appealing ways. Take for example, Tourmaline Spring’s “sacred, living spring water from Maine”. It’s said to be “so naturally pure it exceeds every Federal and State guideline for drinking water straight from the ground.”

There’s also Fountain of Truth Spring Water, which believes water is “perfect just the way it is.”

However, since food-safety experts like Marler warn against it, maybe we should err on the side of caution and reach for other varieties of water until further notice.