The objective of this work was to develop a reliable, ragged high‐performance liquid chromatographic (HPLC) method for determination of trace levels of bromate (< 10 μg/l) in bottled water. HPLC separation was achieved by ion interaction chromatography using a C‐18 reversed‐phase column and a mobile phase consisting of methanol/water (20:80, v/v) with tetrabutylammonium acetate as the ion interaction reagent. A post‐column reaction based on oxidation of o‐dianisidine in acidic solution to a product detected at 500 nm provided selective measurement of the oxidants. The limit of detection and the limit of quantitation were 1 and 3 μg/l, respectively. Iodate, chlorite, and nitrite were chromato‐graphically separated from bromate and measured by monitoring the post‐column reaction. Chloride and chlorate at levels that might be found in bottled water did not interfere with the determination of bromate. Bromate was detected in bottled waters at concentrations up to 40 μg/l.