The high cost of virgin (18)O-enriched water has forced many researchers to study methods to purify and recycle enriched water after the first irradiation for the production of radiopharmaceuticals. In our study, [(18)O]H(2)O was purified by ozonolysis and distillation. Analyses showed a large decrease in impurities after this treatment. The purification procedure was carried out after the production of 94 batches of [18F]-FDG, which were manufactured using a GE Minitrace cyclotron and a GE Mx TracerLab synthesizer. Saturation yields after bombardment, using virgin and re-purified water were, respectively, 2864+/-204MBq/muA and 2727+/-167MBq/muA, a decrease of 5.5%. The decrease in [18F]-FDG yield, from 67.2+/-0.7% to 65.5+/-0.9%, can be ascribed to the irradiation step only.