Hard water is mains water that has a high dissolved minerals content, specifically calcium and magnesium. It can be recognised by a build up of minerals, commonly known as limescale, in systems and devices where the water is used.

Hard water arises from the ability of water to act as a solvent. As it moves through soil and rock, minerals are dissolved and held in the water in solution. As the mineral content increases so does the hardness of the water.

A number of tests can be used be used to determine if water is hard, ranging from the simple lather test to more sophisticated methods of testing hardness such as the wet titration method, or the use of online analysers.

The most effective method of softening hard water is ion exchange. Typically, feedwater enters a water softener and passes through an ion exchange resin, which causes the replacement of calcium and magnesium ions with sodium ions to produce softened water. Periodically, the exchanged calcium and magnesium is removed from the resin by regeneration using salt solution automatically supplied from a brine tank.

For more information on the latest water purification systems that effectively soften hard water, click here.

deionised water | distilled water
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