The efficiency of zone freezing for potable water treatment to remove inorganic impurities was examined. The content of impurities in model solutions before and after zone freezing was evaluated by neutron activation analysis with the formation of ⁵⁶Mn, ^116m In, and ¹⁹⁸Au radionuclides. The zone freezing procedure is the most efficient at low ice front velocities (no greater than 0.15 cm h^-1).