Water distribution system network models are used to simulate both hydraulic and water quality characteristics in water distribution systems. This study provides the first comprehensive evaluation of a multi-species chloramine model through the use of field-scale measurements and distribution system network modeling. Hydraulic and multi-species water quality simulations were performed using EPANET-MSX. This investigation was used to determine knowledge gaps between actual distribution system performance and advanced water quality models. The multi-species model was found to represent some species satisfactorily, while other species were poorly characterized throughout the distribution system. These inconsistencies may be attributed to reactions at the pipe wall, biological nitrification, or misrepresentation of network hydraulics, which were not considered in the model.