You might be talking about ice but hard water is sourced from limescale rock and the limescale is in the water and that is what you get in your kettle when you dont filter the hard water.

Forms of Calcium is what makes hard water hard

Hard water is potable (drinkable).

How can we deal with hard water

No. There is different types of hard water.There is slightly hard, moderately hard, hard and very hard water.And as for soft water it has to have less than a grain of calcium or magnesium. Hard water isn't as useful as soft water.