Large-scale enterprises with high potential to pollute need to be licensed, properly supervised and monitored during and after their operations to avoid and/or mitigate impacts in their areas of influence. The São Mateus Stream Basin (SMSB), located in rural area of Juiz de Fora (MG), is impacted by several activities, highlighting a deactivated landfill and an industrial park. This study monitored the concentration of heavy metals in the waters of the main tributaries of the SMSB. Strategic points were selected in each sub-basin, before the mouth and meeting of the Bocaina, Salvaterra and São Mateus Streams, measured monthly between January and December 2014 using the Metalyser probe, and applying the Contamination Index (CI). The CI results showed that the enterprises located in this basin, especially the Park Sul and Salvaterra Landfill in the Bocaina and Salvaterra Streams, respectively, are negatively impacting the quality of these waters. Metals such as Hg, Cu, Pb and Zn were the ones that most violated CONAMA Resolution 357/2005, directing management in order to control the sources of these metals, which are cumulative in organisms and damage the whole trophic chain. The inhabitants of this rural area are not served by any water concessionaire and make use of springs and wells below the level of these streams.