Documents the long-term effects of disinfectant changes on distribution system water quality. Examines information collected from water utilities that have implemented changes in their disinfection strategy in order to document benefits and adverse consequences in water quality parameters. Provides guidance on how water utilities could evaluate potential changes in distribution system water quality due to changes in disinfection practices. Also provides recommendations to optimize water quality after a change in disinfection practices. Research partner: USEPA. Published in 2007.