The story of corroded pipes and lead poisoning in Flint, Michigan – and its devastating consequences for children – might never have leapt into the national conscience without one determined pediatrician. Dr. Mona Hanna-Attisha documented and publicized the problem, enduring attacks on her credibility along the way, and now fights for interventions to mitigate the impact. But ultimately, this is not the story of a single city, one vulnerable population, or an unusual government failure, but rather the tip of a national epidemic. Just how big is the problem? What can be done about it?