What is the difference between hard and soft water

A. Essentially it boils down (excuse the pun) to mineral content. Hard water filters into our water supplies through soft rock, picking up minerals such as calcium and magnesium on the way, whereas soft water actually passes through hard rock, such as granite, and picks up virtually no minerals at all, making it 'soft'.

A. People in hard water areas are often concerned by the build up of scum or the fur that you find in the kettle, as it looks unhealthy. However, if anything hard water is probably the healthier of the two as both magnesium and calcium are known to help prevent coronary heart disease by reducing blood pressure. Calcium is also, of course, an important component in healthy teeth and strong bones.

A. Many people in hard water areas use water softeners to make appliances work better and prevent clogging and furring up of pipes. Softening is also popular because soap lathers better in soft water.

But most water softening involves introducing sodium (a component of salt) into the water and experts now recommend softened water is not used for drinking, especially for those on a low salt diets or for premature babies, whose kidneys can not cope with high levels of sodium. Softened water has also been shown to release traces of lead from older pipework into the supply.

A. Perhaps the most common addition is fluoride. Fluoride, which occurs naturally in water, helps children produce strong adult teeth. However, if too much fluoride is taken in it can lead to fluorisis, where teeth are turned an unsightly brown colour.