In today’s date when we talk about purity of things nothing can be placed in the category of being pure. From air to water to soil to food everything is polluted. Pollution can be defined as presence of inappropriate material which may cause harm to living beings. Here we talked about the contaminated water and find out the harmful ingredients present in it. I have studied the presence of toxic metals like copper, cadmium and chromium in our water. Water being the most essential part of once life, one cannot image his life without it. So it is very important to have clean and pure water. Under this we studied the harmful effect causes by the metals and the diseases caused by them. Further various techniques have been studied for water purification.