Monochloramine (NH2Cl) produced from the reaction of free chlorine and ammonia in a process called chloramination, is generally considered to be a leading candidate as an alternative disinfectant to replace free chlorine which is known to produce a variety of potentially mutagenic and carcinogenic organic by-products. However, while chloramination produces fewer organic byproducts, recent work has shown that at least one unidentified inorganic decomposition product is formed. The existence of an unidentified product should be a cause of concern because of potential health effects. This research focus on the characterization, identification, and quantification of the unknown(s) produced in chloraminated drinking water under a variety of reaction conditions. This will be done by 1) conducting detailed mass balances on chlorine and nitrogen, 2) developing methodology to separate and concentrate the unknown(s), and 3) applying mass spectrometry and NMR techniques to characterize structure. Expanded research is being funded by a grant from AWWARF.