The Brăteni Lake is used for fishing and leisure. A lot of fish species grow in this lake and many birds and ducks live and nest in this area. A total of 12 sets of surface water samples were collected from three representative points from Brăteni Lake, during 2015 and 2016 for three seasons (autumn, winter and spring). The samples were taken bi-monthly. In situ, using a portable multiparameter WTW Multi 350i, were determined the physico-chemical parameters like: pH, EC, TDS, ORP, and salinity. In laboratory by using an ion chromatograph (IC500 Dionex) were analysed the following cations: NH₄⁺, Mg²⁺, Ca²⁺, Li⁺, Na⁺, K⁺ and anions F ^-, Cl^- , NO₂^-, Br- , NO₃^- , PO₄^3- , SO₄^2-. The content of heavy metals (Cd, Pb and Fe) was analysed using an atomic absorption spectrometer (ZEEnit 700 Analytik Jena). The cations concentration varied between: 56.31 – 75.97 mg/L for Na⁺, 20.44 – 26.66 mg/L for K⁺, 35.92 – 54.80 mg/L for Mg²⁺, 67.83 – 144.22 mg/L for Ca²⁺. N-NH₄⁺ was found only in one sample (0.3 mg/L) and Li⁺ was found in three samples (0.25 – 0.26 mg/L). The anions concentration varied between: 26.78 – 48.93 mg/L (Cl^-), 0.20 – 0.51 mg/L (F^-), 0.19 – 4.07 mg/L (N-NO₃^-), 124.77 – 193.51 mg/L (SO₄^2-). Lead ranged between 3.98 and 33.01μg/L and iron had levels between 0.02 and 0.6 mg/L. Using the obtained results, sodium adsorption ratio (SAR) and Kelley’s index (KI) were calculated, in order to determine if the water is suitable for irrigation.