Water is life. Water is the very important element which plays the important role in the development of our ecology. But due to the discarded of waste from the industry or any other human activity into the water resources water get polluted. Among the treatments available for the water, coagulation found to be the best one. Coagulation is done with the various chemicals like Alum; sodium Aluminate etc. Other than these chemicals polymers can prove the best. This article gives the details about the applications of polyelectrolyte which are basically the types of polymers.