This study evaluates the water quality for human consumption in the municipalities of Sincerín and Gambote. It was measured through physico-chemical (color, turbidity, conductivity, pH, dissolved oxygen, hardness, and heavy metals) and microbiological (total coliforms, Escherichia coli) parameters before and after a partial form of water treatment was used (alum and chlorine addition in Gambote and Sincerín municipalities, respectively). This investigation was done in accordance with the maximum permissible values established by the Resolution 2115 of 2007 of the Ministry of Environment, Housing, and Territorial Development of Colombia (MAVD in Spanish). Additionally, the IRCA (Water Quality Risk Index) was calculated to determine the degree of risk of disease occurrence. The results indicated concentrations higher than the recommended values for: (a) hardness (in Sincerín); (b) iron (Fe), turbidity (only before being treated), E. coli (in Gambote); and (c) mercury (Hg), and total coliforms. The water supplies of the municipalities presented unsafe IRCA. Therefore, it is expected that the results of this study could be used for proposing strategies for improving these conditions by means of the design and implementation of an adequate treatment system.