Objective: To analyze the microbiological quality of three tributaries of Caño Grande by estimating and comparing the indicator groups of quality according to Colombian regulations. Method: Sampling was carried out from September 2022 to January 2023. For each monitoring in September, November and January, 34 samples were taken, and for each monitoring in October and December, 30 samples were taken, following the protocol of the Colombian Technical Standard NTC 813. The determination of the indicator groups was performed using the multiple tube method and plate count. Findings: For the microbiological quality analysis, the results were compared with the permissible ranges described in Colombian regulations. 86% of the analyzed samples from Caño Grande, 66% of the catchment points, and 33% of the filters in use were above the permissible ranges for Fecal Coliforms. 100% of the analyzed samples from Caño Grande, 100% of the catchment points, and 83% of the filters in use were above the permissible ranges for Aerobic Mesophiles. 100% of the analyzed samples from Caño Grande, catchment points, and filters were above the permissible ranges for Molds and Yeasts. Novelty: The results of this first study recommend continuing monitoring to compare results over time and guide the community in implementing methods to improve resource conditions. Keywords: Monitoring; Quality; Regulations; Determination; Microbiological