When talking about New York pizza and bagels and (at least historically) when talking about Kentucky bourbon, the local water is often mentioned as a key factor.
Regarding the historical Kentucky water - in parts of the state the natural water sources were high in limestone which was considered an important feature for bourbon (as well as horses). However, regarding New York pizza and bagels I often hear that no amount of copying the recipe will matter if you don't have the water (down to the issue of flying in New York City tap water). So my question is - what exactly is in New York City tap water that is of such value to baking?
Are these discussions on the value of water tied to the lore of these products (Guinness is another product that has a 'water story'), or are there specific regional variations/natural components to water that strongly impact certain foods and beverages?