The present study was undertaken to investigate the heavy metal decontaminating activity of Salvinia molesta from municipal waste water. The waste water was treated with the plant specimen for five and ten days consecutively after which it was analyzed for the estimation of cadmium (Cd), copper (Cu), iron (Fe), nickel (Ni), lead (Pb) and zinc (Zn) by inductively coupled plasma atomic emission spectroscopy (ICP-AES). The waste water was also analyzed before the treatment. The results of the investigation showed that the non-treated samples indicated higher content of Fe followed by Zn in sample Nitta gelatin (NG). It was found that Cu and Ni were present in similar quantities in all samples. A favorable decrease was seen in Zn in all samples and Fe in sample NG after five days of treatment. The concentration of Cu and Fe were found to be below the detection limit in samples collected from Chalakudy (CH), Ernakulam (ER) and Kokkala (KK) after ten days of treatment. Ni was found to be below the detection limit in samples ER and KK. Zn was found to be at a reduced level in samples CH, ER, KK and NG. Cd and Pb were found to be below the detection limit (0.01 and 0.05 ppm) in all four samples before treatment, after five and ten days of treatment. The present findings revealed that S. molesta was efficient in reducing the heavy metal concentration in the waste water, suggesting being a bioaccumulator of these metals.