A renewed emphasis on source water protection/watershed management has resulted from recent amendments and initiatives under the Safe Drinking Water Act and the Clean Water Act. Knowledge of the actual microbial inputs to source waters is critical for efforts to control, eliminate or remediate those inputs. This study evaluated source delineating microbial monitoring tools for use in watershed monitoring, including sorbitol-fermenting Bifidobacteria, Rhodococcus coprophilus, and F-specific RNA coliphage serotypes. These tests all employ standard microbial culturing methods and do not require expensive instrumentation or expertise in molecular methods. Water utilities and water management agencies could therefore use these tests to identify contaminant sources and implement remedial actions to eliminate those sources and their associated pathogen risks. Includes 19 references, tables.