This chapter addresses waterborne pathogen risks in healthcare settings and strategies for infection prevention and control. Waterborne pathogen risks can be significant in healthcare settings, from unexpected incidents of intrusion of water into occupied areas to mitigation of microbial contamination. As a result, water-related problems are among the most challenging infection prevention issues involving the environment of care. Prominent among these is prevention and control of Legionellacontamination of water distribution systems, which is discussed here. However, Legionella risks vary by geographic region, and Legionella is just one of many other microorganisms, including fungi, that can be present in the water distribution system. This chapter attempts to provide an overall approach to assessing risks and developing prevention strategies, including design considerations, routine preventive maintenance for operations and equipment, and remediation measures during floods or utility outages. Water disinfection/treatment options are also discussed, including considerations for use and strengths and challenges of various modalities.