This chapter explores the role of water in human nutrition, public health, and environmental sustainability.  It explains why water is an essential nutrient and highlights its role in health and kidney disease while dispelling hydration myths.  The chapter reveals global disparities in tap water quality, which varies by socioeconomic and geographic factors, and examines the role of fluoride and fluoridation in dental cavities.  It describes the rise of plastics in food containers and critiques designer bottled water, highlighting the roles of BPA, forever chemicals (PFAS), and fossil fuels used in plastic production that contribute to health risks, air pollution, and climate change.  While many plastics are recyclable, the chapter reveals that most end up in the ocean, where they compromise wildlife and threaten biodiversity; microplastics also end up on human plates (and in human bodies and brains), emphasizing the need to reduce plastic production and consumption to protect public health and the environment.