With ever increasingly specific and sensitive diagnostic methods for infectious diseases, it has become recognized that different sources of microbial inputs/contamination to drinking waters are related to different potentials for the presence of pathogenic microorganisms. Coupled with the renewed emphasis on source water protection and watershed management under the Surface Water Treatment Rule and the Long Term 2 Enhanced Surface Water Treatment Rule, many drinking water utilities may be looking towards tools that allow them to discriminate among potential microbial contamination sources in their watersheds. The use of microbial source tracking (MST) tools can also provide a utility with information so that corrective actions can be applied in a more effective and costefficient manner. Even though research into MST methods has spanned several decades, there is no consensus on the best or most reliable method to date. Application of MST tools within a source water protection plan depends on the goals and questions asked by the plan. Two general microbial indicator approaches to MST methods have been studied: the species-specific approach and the organism-specific approach. The species-specific approach looks to quantify microbial indicators associated with a specific "species" of contamination such as human or non-human. The organism-specific approach looks at a single organism such as E. coli and relates subtypes to the various hosts (human and different animal species). The organism-specific approach typically involves development of a geographically relevant library or database of isolates against which unknowns are compared. A third MST approach is to look for chemical markers indicative of sewage or humanrelated wastewater. This presentation will provide an overview of the methods currently being researched and applied. The information provided will include the state of development of each method, some of the strengths and limitations of each method, and the investment in training and equipment needed should a utility decide they want to implement such a method.