I used to have no problem with tap water. I grew up in Cincinnati with parents who, at dinner, filled a pitcher straight from our kitchen sink. In St. Louis during college, I subsisted on campus water fountains. I later moved to New York, which boasts “the Champagne of tap water” and claims it to be the secret ingredient in its bagels. During a two-year stint in Montana, I went on long hikes and sipped stream water, shockingly cold and straight from the glaciers, but other than that, I drank from the tap. And then I landed in Los Angeles, where everyone I met used a filter.