Rare earth elements (REEs) are crucial components in clean energy, electronics, and national defense applications. The demand for more has led to the exploration of alternative REE sources, such as groundwater. In this study, we use REE-selective Bacillus subtilis spores due to their unique adsorptive/desorptive capabilities to extract REEs from the solution. The adsorption process was investigated at different experimental parameters such as pH and initial metal concentration using both groundwater and standard REE spike solutions. Interferences in the groundwater, such as iron and aluminum, have proven to limit the adsorptive capabilities of the spores. The standard Dy solutions demonstrate recovery of 95% Dy3+ using the spores. The groundwater results indicate that none of the seven target REEs were precipitated at pH 4.1 (Fe oxidation), but 50% of Fe and Al were removed. Increasing the pH to 6.1 (Al oxidation), only 2% of Fe and Al remained, while 75% of REEs were lost. Removing interferences led to substantially higher adsorption percentages. These adsorption pH studies demonstrated pH 7 as having the highest adsorption percentages. The spores efficiently adsorbed the seven target lanthanides at 97%, while recovery was ˃90%. There was a stronger binding for Nd, La, and Y but at different pHs. The overall findings suggest that groundwater has the potential to be a viable source of REEs, and this biological adsorption system can be used to extract REEs from various sources.