Why is Hard water so bad?

Hard water "scale" damages everything that it comes into contact with, but there is also the problem  of hard water "scum" as well.

Hard water reacts with soaps, shampoos and washing detergents to form a sticky curd like substance that we know and recognise as scum. It clings stubbornly to the surfaces of baths, basins and showers, and also become embedded into every fibre of clothing and linen and prevent them from ever becoming really clean.  Hard water scale also becomes entwined in the fibres of clothing and linen  so they have the accumulative effect on preventing scale and scum rinsing clear of your washing.

But there is more, much more.Hard water scale is actually very small crystals of dissolved rock, and when water heated, it again forms into rock and persistently builds up to cling to  all surfaces that it touches. Hard water scale will clog up pipework, heating elements in tanks, immersion heaters, dishwashers and washing machines ( have you seen the Calgon ad?) electric shower heaters and pumps and even your kettle and coffee maker. When hard water scale "wraps" itself around all of these heating element it forms into a solid insulator, prevent the heater from reaching the water effectively, so it has to work harder and harder to heat the water, pushing your heating bills higher and higher.