<p>This paper investigates the influence of groundwater level (GWL) on the possibility of dynamic liquefaction in a body of sandy soils under seismic impact. The research methodology consisted in laboratory testing of soil samples using triaxial compression equipment to determine their dynamic strength. The values obtained were compared with cyclic stresses in the soil body that arise under calculated seismic impact scenarios and various GWLs. It was determined that under GWLs below a certain critical level (5.3 m for the studied soil type), the presence of groundwater cannot lead to soil instability under all predicted levels of the seismic impact under consideration. However, under GWLs above this level, a loss of stability becomes possible. Recommendations on mandatory consideration of GWL in designing foundations in seismically hazardous areas are substantiated; engineering solutions for ensuring the dynamic stability of structures are proposed.</p>