Our study is carried out on the trio of thermomineral waters in the region of Khenchela - Hammam Salhin, Hammam Knif, and Hammam Djaarir - Northeast of Algeria. The purpose of this study is to determine the physicochemical and geothermal origin of the thermal spring (temperature, pH, and electrical conductivity). The temperatures of the thermal water samples which were being studied varied from 38 to 72°C; therefore, this variation has a direct relation to the climatic conditions and/or the combination of the water which is derived from various sources in the formation of the thermal spring. Additionally, the pH value of the spring under study is of a neutral to slightly alkaline quality, while its electric conductivities are high, ranging from 3059 μS/Cm to 5007 μS/Cm. The Piper diagrams presented the domination of sodium chloride (Na-Cl) and sodium sulfate (Na-SO4) facies as two types of water in the hydrochemical facies. These facies indicate the mineral composition of the thermal waters, a product from the reservoir by way of geological formations in the subsurface. This is a plausible reason from the chemical changes observed in the fluids and can well be associated with the high influence of water-rock interaction, that is, the formation of sodium bicarbonate water to sodium-chlorinated water formation, where it is linked with the effects of dissolution and salinity in the formation of saliva found in regions with semi-arid climatic conditions. Evaporation would play a major role in increasing the sodium content, while the IIRG plots closer to the industry "α" standard than the other plots. These are the characteristic features of an evaporation-based system. The crucial parameter C serves as a strong indicator of circulation in carbonate reservoirs subject to evaporation.