Surface water reservoirs and aquifers are exposed to contamination by thousands of micropollutants from industrial, pharmaceutical, agricultural and natural origins. Most developed and developing countries implement a water-quality regulation programme to prevent contamination by such chemicals at illegal concentrations. Traditionally, analytical methods based on gas chromatography-mass spectrometry or liquid chromatography with UV/fluorescence detection were used to monitor water quality. These methods require multistep sample preparation and several have low specificity. Nowadays, liquid chromatography tandem mass spectrometry has become a key technique for environmental analysis, allowing the detection of a wide range of polar and nonvolatile compounds. The use of this method has increased the specificity and confidence of identification, while reducing sample preparation to a minimum.