The objective of this research is to determine the effects of changing disinfectants (from free chlorine to chloramines and vice versa) on levels and rates of leaching from lead, brass, and copper components in the distribution system. This project will also study the effects of changing disinfectants on galvanic coupling on metals release and existing scales, and will advance our understanding of the nature of lead and copper solids. This report summarizes existing information regarding the effects of changing disinfectants on rates and concentrations of metals leaching from distribution system components. Knowing that within the next five years, more than 100 sizeable utilities will undergo disinfection conversion to chloramines, AwwaRF chose to publish the results of this research in two parts. Part 1 (this report) was published in October 2006, within a few months of the start of the project in order to provide timely information to utilities concerning the effects of changing disinfectants and compliance with the Lead and Copper Rule. Part 2 (Laboratory Studies, Pipe Loop Testing, and Field Sampling) should be available by early 2009, after the completion of the laboratory and field sampling that will be conducted through May 2008.