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See also: Water softening. Soft water is surface water that contains low concentrations of ions and in particular is low in ions of calcium and magnesium. Soft water naturally occurs where rainfall and the drainage basin of rivers are formed of hard, impervious and calcium poor rocks.ecause soft water has few calcium ions, there is no inhibition of the action of soaps and no soap scum is formed in normal washing. Similarly, soft water produces no calcium deposits in water heating systems. Water that is not soft is referred to as hard water.
Most water lies somewhere in the spectrum between soft and hard. And if you have water on either extreme end of the spectrum, you've probably noticed the effects. If you have a rough time getting soap to lather or rinse from your skin, then you probably have very soft water.