Can Pure Water Be Radioactive? Tritiated Water and Distillation

Pure water (H₂O) can be radioactive through a specific mechanism: tritiated water, where one or both hydrogen atoms are replaced by tritium (³H, a radioactive hydrogen isotope). The molecule is still chemically water, but it is radioactive. Tritium occurs naturally (cosmic rays hitting the atmosphere) and artificially (nuclear reactors, weapons testing). Tritiated water behaves identically to normal water chemically — it evaporates, condenses, and participates in all normal water chemistry. Distillation cannot remove tritium from water because tritiated water has the same boiling point as regular water (they co-evaporate). If you distill tritium-contaminated rainwater, the tritium comes through with the distillate. Distillation DOES remove: dissolved radioactive minerals (radium, uranium, cesium), particulate contamination, and non-volatile radioactive substances. These stay behind in the original vessel. For practical purposes, rainwater tritium concentrations are far too low to be dangerous. The concern with tritiated water is primarily in nuclear facility contexts where concentrations are much higher.