Longtime Santa Fe resident and 'Game of Thrones' author George R.R. Martin opened his new bar, Milk of the Poppy, last March.

"Until further notice, customers are advised not to drink, cook with, or brush teeth using tap water," officials said.

You—and perhaps RFK Jr.—might think that whole milk is at least more “natural,” given that “whole” is in its name. But it’s ...