Peatlands are lands transitional between terrestrial and aquatic ecosystems where the water table is present on the surface or near it, or still presents itself in flooded conditions. Despite the recognized importance of these environmental matrices in the storage of organic carbon and water, little information has been known in the literature about their influence on the surface water quality. This study aims to evaluate the water quality from peatlands in the spring of the Rio Campo Belo, in Itatiaia National Park, Itatiaia–Brazil. The spring water quality from peat profiles was based in geochemical parameters, such as temperature, dissolved oxygen (DO), electrical conductivity, pH, turbidity, dissolved organic carbon (DOC), total organic carbon (TOC), silica, ions, and trace elements (Al, Sb, As, Cd, Co, Cu, Cr, Sn, Fe, Mn, Mo, Ni, V, Ga, Rb, Sr, and Zn) on spring water and peat core samples. The highest DO values observed in the spring waters that leachate water and may be related to the lower water temperature, as well as the movement of water. The DOC values were relatively low suggesting no difference between the spring water and the water leached (1.6 and 1.7 mg L−1, respectively). Higher values of ions and trace elements in the leaching water from core peat demonstrate a greater contribution of the peatland to the concentration of these ions in spring water. Increase in TOC values did not cause an increase in pH values, in contrast to the observed with the organic matter removal, resulting in increase of pH values.