Water in nature is composed of dissolved minerals. The most natural water is the one with calcium, magnesium, sodium, potassium...
Nowadays it is difficult to have access to pure, natural water. The pipes that supply hundreds of thousands of people with water require the use of chemicals to eradicate any bacteria or foreign organisms that we might ingest.
Bottled water is not a healthy alternative either, as it contains endocrine disruptors (small plastics) that migrate into the water, are absorbed into our bodies and can affect our hormone system.
The most economical and environmentally friendly solution is to filter our tap water to remove the added chemicals while still making the most of the natural minerals it contains.