The U.S. Safe Drinking Water Act (SDWA) marked its fiftieth anniversary in 2024. The SDWA significantly improved drinking water quality over its first five decades, making tap water safer for hundreds of millions of Americans. However, substantial drinking water challenges persist in the United States, including aging infrastructure, novel contaminants, and profound social inequities. This introductory chapter provides an overview of the SDWA’s origins, structure, and evolution, highlighting its successes and identifying critical gaps. It explores challenges such as disproportionate health-related violations in low-income, rural, Black, and Hispanic communities, regulatory gaps for private wells and commercial water, and the immense financial burden of infrastructure replacement. Further challenges include assessing relative risk for emerging contaminants, fragmented governance, workforce development, and risk communication. This introductory chapter sets the stage for the book’s subsequent chapters, each of which offers rigorous research and concrete recommendations to reimagine the SDWA for the next fifty years, aiming for a more resilient, sustainable, healthy, and just drinking water future.