This issue brief examines the pathways through which climate change affects public health via its impacts on water and sanitation systems in the United States. Climate change is intensifying threats to public health by disrupting water and sanitation systems. Hazards such as extreme temperatures, drought, wildfires, flooding, extreme storms, and sea level rise are increasingly compromising access to clean water and safe sanitation, elevating risks of waterborne disease, mental health challenges, economic hardship, and social inequities. These impacts are especially severe in communities already facing systemic barriers to safe water access, sanitation, and health care, including Indigenous, rural, low-income, and other frontline communities. The brief synthesizes existing evidence at the nexus of water, climate, public health, and equity, highlights cross-cutting issues, and identifies priority research gaps in the United States. It concludes with policy recommendations intended as a starting point for policy development and further evaluation. 

• Climate change is intensifying threats to public health by disrupting water and sanitation systems. 

• These impacts are especially severe in communities already facing systemic barriers to safe water access, sanitation, and health care. 

• Because climate change disruptions to water and sanitation systems are inherently cross-sectoral, siloed approaches are insufficient. 

• Significant gaps persist in both research and policy at the nexus of climate change, water and sanitation equity, and public health in the United States. 

• Responding effectively requires integrated, cross-sectoral frameworks and approaches that align infrastructure investment, public health planning, and community-led adaptation with climate resilience goals.