You may be wondering why your tap water tastes different from bottled water. Both kinds have to satisfy federal government rules covering purity and contamination. So how can one be so different from the other? And why is tap water the one that can be a serious health risk for your family?

These are great questions. The Environmental Protection Agency is in charge of setting standards for tap water. The Food and Drug Administration handles bottled water, like the kind you might buy in a grocery store. And the FDA’s standards for purified water are often far more strict.

Yes, purified water starts out as tap water. But it runs through many different filtration systems before it ever goes into the bottle. The International Bottled Water Association, a trade group for bottled water companies, says they include “reverse osmosis, distillation, micro-filtration, carbon filtration, ozonation, and ultraviolet (UV) light.”

And if you’re worried about PFAS, the “forever chemicals” that seem to be everywhere, they started applying strict limits on PFAS back in 2019.