No pizza in America can compare to a thin, foldable New York slice. Likewise, authentic New York bagels are the only acceptable breakfast rolls. And it’s not just hometown bias. Now, the superiority of New York dough can be substantiated by the sheer excellence of one of its main ingredients: water.

New York City is home to some of the highest quality tap water in the world; it flows to our faucets from reservoirs in the Catskill Mountains of Upstate New York. New York is one of just five cities in the United States that does not need its water to be filtered, and this lack of filtration lends the water its unique flavor. The water contains natural deposits of calcium, magnesium and sodium, and it is treated with chlorine to kill bacteria. Phosphoric acid in the water lines and plumbing pipes prevents lead from entering the water supply, whereas sodium hydroxide reduces corrosiveness and potential lead exposure. Additionally, the fluoride in the water strengthens teeth. The bottom line is that New York water is one of a kind. Since water is such a prominent ingredient in pizza dough, the dough in turn also tastes amazing.

Pizza chefs across the country are convinced that the minerals in New York water strengthen wheat protein and make dough crispy on the outside and chewy on the inside. David Spatafore, owner of Village Pizzeria in Coronado, California, is so convinced by this theory that he ships New York water across the country to use for making his dough. Independent taste tests seem to confirm the superiority of pizza made with this special water.

Others have resolved to replicate the taste of New York water on their own. Rosenberg’s Bagels of Denver, Colorado advertises “real New York bagels with real New York water”; owner Josh Pollack installed his own water system which he says produces water identical to that of New York. Brooklyn native Larry King invested in a similar operation, Brooklyn Water Bagels of Delray Beach, Florida, which also filters its water and enhances it with minerals.

Despite the success of New York water, both in the city and beyond, it has its skeptics. J. Kenji López of Serious Eats performed a double blind taste test for such notable foodies as Ed Levine, Adam Kuban and Jeffrey Steingarten, but he found no definitive correlation between mineral-enhanced water and better pizza taste. America’s Test Kitchen compared bagels made with water from Brookline, Massachusetts to those made in Brooklyn, and the results were similarly inconclusive.

Water, of course, is not the only factor that contributes to the taste of a slice of pizza. The quality of the ingredients, the time and temperature at which the pie is cooked and even the age of the oven affect the taste of the final product. Regardless of the scientific accuracy of the theories surrounding New York pizza’s superiority, we can all be sure of one thing: there must be something in the water.

Email Abigail Weinberg at [email protected].