It's simple - because it's ionized!
The Ionization process creates water molecule clusters that are half the size of regular water molecule clusters.
This is why Ionized Water is sometimes referred to as "reduced water" because it has become reduced in size from a 12 water molecule cluster to 6 water molecule cluster.
This makes the water much more hydrating because it flows through our body tissue more easily, thus pushing toxins out of our system.
It is this detoxifying effect that sometimes gives people headaches and diarrhea and why there are weak, medium, and strong alkaline water levels plus clean water for drinking on our ionizers.
All water ionizers should have more than one level.