An abundance matrix (BM_OTU.xlsx) contains rows as OTU, columns as samples, and entries representing the abundance of each OTU as a ratio of all sequences obtained for each individual sample. This dataset is associated with the following publication: Gomez-Alvarez, V., and R. Revetta. Monitoring of Nitrification in Chloraminated Drinking Water Distribution Systems With Microbiome Bioindicators Using Supervised Machine Learning. Frontiers in Microbiology. Frontiers, Lausanne, SWITZERLAND, 11: 2254-2267, (2020).