The drinking water and wastewater industries are interested in developing a better understanding of sources of fecal contamination. Microbial source tracking (MST) offers the potential to apportion the contribution of various animal groups to this contamination. However, while there are many methods available there is no clear indication as to the most appropriate approach. There has been little systematic comparison of methods and only a few blind trials, and issues of reproducibility, accuracy, sensitivity, specificity, resolution, and robustness need to be addressed. There is confusion...