Pathogenic bacteria can move through soil to contaminate drinking water. The study looked at how Escherichia coli 652T7 moves through different soil depths. Results showed that bacteria moved more easily through deeper soil layers. This was because deeper soil had less organic matter, iron oxides, and zeta potential. Bacteria moved more in intact soil than disturbed soil due to larger pores and less connectivity. Tilling and adding organic matter to soil can help reduce bacterial movement.