Complex environmental health emergencies and outbreaks associated with drinking water trigger public health responses because of their potential for causing community-wide illness and disruption. These emergencies can be caused by emerging pathogens, chemicals, toxins, natural disasters (e.g., floods, hurricanes), or aging infrastructure. This learning lab will demonstrate the value of existing water-related tools and guidance for state/local health departments to respond to complex water emergencies describe concrete actions for improving public health preparedness planning and response.