The goal of this first AwwaRF project on dissolved organic nitrogen (DON) is to document DON occurrence and provide information on its chemical characteristics and reactivity towards metal hydroxides and oxidants/disinfectants. The research uses both well-developed DON analytical methods from the fields of ecology and oceanography and innovative DON quantification methods tailored for the drinking and reclaimed wastewater industry. Objectives included: develop an accurate DON quantification method for drinking waters and a comprehensive assessment of DON occurrence in raw/finished drinking waters and reclaimed wastewaters, evaluate a suite of analytical tools for characterizing DON structure, and numerous others.