Data for opportunistic pathogen detections and physicochemical parameters in drinking water. This dataset is associated with the following publication: Zhang, C., N. Sienkiewicz, I. Struewing, J. Mistry, H. Buse, Z. Hu, and J. Lu. Reconsider the burn: The transient effect of a chlorine burn on controlling opportunistic pathogens in a full-scale chloraminated engineered water system. SCIENCE OF THE TOTAL ENVIRONMENT. Elsevier BV, AMSTERDAM, NETHERLANDS, 933: 172690, (2024).