Natural flowing water (in streams, rivers) contains ions of calcium, magnesium, sulfur, sodium, chlorine, potassium and fluor, with chlorine content around 10mg

Natural flowing water (in streams, rivers) contains ions of calcium, magnesium, sulfur, sodium, chlorine, potassium and fluor, with chlorine content around 10mg/l. Tap water without chlorine treatment would be devoid of most of those and that could be argued unhealthy. That is - assuming the natural levels are healthy for us.