Disinfectants in drinking water can interact with natural organic matter (NOM) to form disinfection by-products (DBPs). Halogenated furanones (including MX and MCA) are a group of emerging DBPs that can account for a significant amount of the total mutagenicity found in drinking water. Source water characteristics and NOM removal capabilities of coagulation can greatly influence the formation of DBPs. This project examines the effects of bench scale coagulation and chlorination tests on NOM removal, DBP formation, and genotoxicity. NOM was characterized using liquid chromatography-organic carbon detection (LC-OCD). Experiments with Ottawa River, Otonabee River, and Lake Simcoe waters show that DBPs decreased with increases in coagulant dosage, due to the removal of NOM during coagulation. DBP formation and speciation was then compared with NOM content to identify specific fractions that contribute to the formation of these DBPs. Genotoxicity was directly linked to MX presence in chlorinated waters.