The detection of explosives is of paramount importance in the areas of internal security and military activities. Tracking down clandestine laboratories manufacturing homemade explosives, and in particular those made from organic peroxides (triacetone triperoxide TATP, methyl ethyl ketone peroxide MEKP, hexamethylene triperoxide diamine HMTD), is a major issue in the fight against terrorism worldwide. During the synthesis of these peroxide-based explosives, significant quantities of precursors or residues of explosives may be discharged into wastewater and then in environmental waters. Some of these precursors (e.g. acetone or hydrogen peroxide) are used for other applications (e.g. solvents, bleaching agents, medical and industrial products) and are therefore not specific of the manufacture of explosives. However, they can provide a first indication of the location of the production site through on-line monitoring of wastewater. Many analytical techniques exist for the trace analysis of explosives on post blast surfaces or for the quantification of traces of hydrogen peroxide in biological systems (topics already reviewed elsewhere). However, the application of these techniques to water and wastewater monitoring remains challenging. In this review, water sample preparation and instrumental methods applied (or at least adaptable) to water analysis for the quantification of peroxide-based explosives (PBEs) and of their major precursors are reviewed and discussed. Sample preparation by solid-phase extraction (SPE) is thoroughly investigated for organic peroxides and some precursors. Analytical methods such as electrochemistry, spectroscopy, chromatography coupled to mass spectrometry or flow injection techniques are presented for their application to PBEs. The advantages and disadvantages of the different analytical techniques show that some of these techniques could be combined to develop low-cost, easily transportable, and miniaturized methods for automated in-situ analyses of explosives and their major precursors.