Pollution of water-bodies is a major concern in today’s era. Idol immersion activities during certain festive occasions are adding to the pollution load of the water- bodies. Non-biodegradable materials and synthetic paints used for making these idols are posing serious threat to aquatic life and environment. Water quality assessment is an important exercise to evaluate the nature and extent of pollution in order to take appropriate control measures. The present work is concern about the Water quality assessment to evaluate the nature and the extent of pollution in water body. Two major idol-immersion sites Shivaji Park, Mumbai and Masunda lake, Thane were selected for taking marine water sample and fresh water sample respectively in present study. Pre-immersion, immersion and post-immersion samples were collected from three sites stations and analyzed for various water quality parameters such as pH, Total suspended solids (TSS), Total dissolve solids (TDS), Total Solids (TS), turbidity, conductivity, hardness, Dissolved oxygen (OD) and COD. The variations in the values of these parameters were more prominent in fresh water samples than marine samples. It was observed that the values of these parameters significantly increased during the immersion period and then declined in the post-immersion period. However the general trend observed was : immersion > post-immersion > pre-immersion values. pH declined slightly during immersion period whereas DO showed only slight variations in the pre-immersion, immersion and post-immersion samples.