The sustainability of freshwater supplies is a growing concern that is being jeopardized by population growth, aged infrastructure, changing climate patterns, and increasing demands by economic activities. Regions that are experiencing severe water drought and scarcity are already developing and implementing technologies to augment their water resources from wastewater effluents. The reuse of wastewater effluents requires the practice of disinfection to prevent outbreaks of waterborne diseases. Disinfectants can also react with natural and anthropogenic constituents to form disinfection by-products (DBPs) that pose a potential health problem caused by long-term exposure. However, the formation of DBPs from advanced treatment of treated secondary wastewater effluents for potable reuse has not been well characterized. In this study, a highly sensitive analytical method was developed to characterize 25 DBPs from 5 chemical classes in recycled wastewaters using a gas chromatography tandem mass spectrometer (MS/MS).