A Micro Seismic Resonance (MSR) method has been developed to improve seepage characterization through, beneath, and around dams. MSR is a passive seismic method that detects zones of higher permeability in the foundation and fill materials of a dam. The MSR geophysical method has been used on many dam seepage investigations. Two particular case studies will be presented where seepage flow paths were successfully identified for dams in Canada and the U.S.