The entire Earth is made up of 75% of water and the rest of the land. Water is also present in our body in major quantity.
If we are going to drink impure water, it will be extremely dangerous for our life. The common impurities in water are arsenic, fluoride, iron, sodium, magnesium, and chlorides. These can cause diseases like cholera, typhoid, dysentery, malaria, etc. There is RO water purifier in almost every house today. But if you want to keep it working well, you need to repair and maintain it.