ABSTRACT: In general, the rock types; basalt, andesite, altered andesite, tuff, dacite, and marl intercalating with volcanics, have been identified lithologically in the Değirmendere Basin. In the basin, there are many springs with a high carbon dioxide content and total dissolved solids, all of which are related to tectonic lines. Of these, four springs have discharge rates, pH, specific electrical conductivity (SEC) and total dissolved solids (TDS), respectively, 46- 158 ml/sec, 5.32-6.99, 603-1899 μS/cm and 380-1230 mg/l. It is determined that silicate weathering, carbonate weathering and ion-exchange type water-rock interaction processes were effective on the chemical evaluation of the Ca-HCO3 water type springs. The Chloro Alkaline Indices (CAI), which are calculated to explain the ion-exchange, indicated a reverse exchange. Based on δ18O-δ2H correlation, the springs which have a meteoric origin lie on the Eastern Black Sea Metoric Water Line. According to the isotopic values, the chemical composition of the young and shallow circulating springs was developed during circulating to the upper parts of the volcanic rocks where an intense weathering was observed. The concentration of Ba, Sr and Zn are high as in the rocks. Br (0.036-0.070 mg/l) and Cr (0.062 mg/l) values of the springs exceed the limit recommended in the Natural Mineral Water Regulation (2004).