Thermal osmosis is one of the lesser understood water transport drivers in PEM fuel cells. Kim and Mench's 2009 thermal osmosis model has been widely used in system-level fuel cell models to predict net water flow through the membrane. However, because their experiments were liquid-liquid across a hydrophobic membrane, it may have given rise to two-phase membrane distillation which may have been inadvertently lumped in with single-phase thermal osmosis. Membrane distillation always occurs when liquids are at two different temperatures are separated by a hydrophobic membrane. In this case, the liquid is transported in the direction of hot to cold through phase change which is an entirely different mechanism than single-phase thermal osmosis even though both require a temperature difference. What makes experimental studies in fuel cell membranes difficult is that only the net water flow can be measured, and that is the result of numerous simultaneous drivers such as potentials in chemical, voltage, temperature, and pressure. In prior thermal osmosis research such as Kim and Mench's, experiments were performed with liquid phase water, and in that case not accounting for membrane distillation may have thrown off the magnitude of the single-phase thermal osmosis contribution. In the current research, a method is presented for how to data mine prior research to properly isolate single-phase thermal osmosis and to determine its true magnitude.