Fecal pollution in recreational and drinking source waters can result in outbreaks leading to the transmission of disease. Information on the sources of fecal pollution is important because the level of human health risk can change from one pollution source to another.The Centers for Disease Control and Prevention (CDC) is utilizing Microbial Source Tracking (MST) tools developed by U.S. Environmental Protection Agency (EPA) scientists for environmental investigations of waterborne outbreaks. This webinar will provide an overview on EPA's MST method and its use in a recent waterborne outbreak to help confriom a source of norovirus.