Environmental toxins seriously threaten water quality and public health. These pollutants are generated from industrial, agricultural, and urban runoff; wastewater facilities; landfills; and natural sources. We contaminate industries and discharge heavy metals, microplastics, and chemicals; agriculture contributes pesticides such as glyphosate, fertilizers, and animal waste. Other polluters in water systems include pharmaceuticals (such as antibiotics and hormones) and personal care products, such as phthalates in food packaging. Roads and rooftops run off urban runoff that carries hydrocarbons, heavy metals, and litter to nearby water bodies, and wastewater treatment plants often do not remove emerging contaminants. In addition, harmful chemicals are released from landfills and hazardous waste sites through leachate, runoff, and atmospheric deposition of pollutants from emissions to land and water. Natural sources, including algal blooms and radionuclides, exacerbate water contamination. Current changes in atmospheric composition necessitate regulations, developed approaches to reduce industrial pollution, and consensus among environmental stakeholders to protect water resources for use and to preserve ecosystem health for generations to come.