Water is primarily supposed to be H20. But, is it?
Even the freshwater that you get from the tap has several impurities such as lead, nitrates, and other inorganic substances.
In most homes, you will find a reverse osmosis system to convert tap water into potable water. Reverse Osmosis is a technology, that allows tap water to pass through polymer membranes with high pressure. The membranes purify the water by filtering out the impurities, bacteria and other viruses.