The Solution Is The Problem
While water is in the ground, it picks up soluble bits of whatever it passes through. While this can mean contamination that makes the water unfit to drink, in many cases it simply means that the water contains minerals found in the earth. Of these, calcium and magnesium are of particular importance because they affect the water's ability to function in our homes. These minerals make our water hard.
One effect of hard water is that soaps and detergents lose some effectiveness. Instead of dissolving completely, soap combines with the minerals to form a coagulated soap curd. Because less soap is dissolved, more is required. And the sticky insoluble curd hangs around--it clings to the skin and may actually inhibit cleansing. Washed hair seems dull and lifeless.
In the laundry, things aren't much better. The soap curd can work its way into your clothes as they're being washed in your automatic washing machine. This can keep dirt trapped in the fibers, and it can stiffen and roughen the fabric.
In addition to affecting the actual washing process, insoluble soap deposits leave spots on everything you wash—from your dishes to the family car—and a soap film will build up in your bath and shower.
Another reason to be concerned about hard water is its effect on your plumbing system. Calcium and magnesium deposits can build up in pipes, reducing flow to taps and appliances. In water heaters, these minerals generate a scale buildup that reduces the efficiency and life of the heater.