WHAT IS LIMESCALE?

Limescale comes from limestone deep under ground.

It is deposited in our water as the supply slowly filters through the limestone having first fallen as rain.

It deposits in your kettle when the water is boiled.

Lime and the carbon dioxide are held in equilibrium when the water is cold.

When heated and boiled carbon dioxide bubbles are produced and the spare limescale still suspended in the water is no longer in balance so it adheres to any surface it can in this case the inside of your kettle.