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A rapid, sensitive and precise method for the determination of bromate (BrO 3 − ), nitrate (NO 3 − ) and nitrite (NO 2 − ) in drinking water was developed with Ultra performance Liquid Chromatography–Mass Spectrometry (UPLC–ESI/MS). The elution of BrO 3 − , NO 3 − and NO 2 − was attained in less than two minutes in a reverse phase column. Quality parameters of the method were established; run-to-run and day-to-day precisions were <3% when analysing standards at 10 µg L −1 . The limit of detection was 0.04 µg NO 2 − L –1 and 0.03 µg L –1 for both NO 3 − and BrO 3 − . The developed UPLC–ESI/MS method was used to quantify these anions in metropolitan water from Saudi Arabia (Jeddah, Dammam and Riyadh areas) and commercial bottled water (from well or unknown source) after mere filtration steps. The quantified levels of NO 3 − were not found to pose a risk. In contrast, BrO 3 − was found above the maximum contaminant level established by the US Environmental Protection Agency in 25% and 33% of the bottled and metropolitan waters, respectively. NO 2 − was found at higher concentrations than the aforementioned limits in 70% and 92% of the bottled and metropolitan water samples, respectively. Therefore, remediation measures or improvements in the disinfection treatments are required. The concentrations of BrO 3 − , NO 3 − and NO 2 − were mapped with Principal Component analysis (PCA), which differentiated metropolitan water from bottled water through the concentrations of BrO 3 − and NO 3 − mainly. Furthermore, it was possible to discriminate between well water; blend of well water and desalinated water; and desalinated water. The point or source (region) was found to not be distinctive. [ABSTRACT FROM AUTHOR]