Insoluble impurities are those impurities that do not get dissolved in the water. Sand and germs are examples of insoluble impurities. Filtration is an important method for removing insoluble impurities present in water. In the filtration method, impurities are removed with the help of a filter paper, cotton can also be used as filter paper. Evaporation and distillation are methods for removing soluble impurities present in the water like salt or sugar.