A water softener is a unit that is used to soften water by removing the minerals that cause water to be hard.

Hard water causes a higher risk of limescale deposits in household water systems. Due to this, pipes are blocked and the efficiency of hot boilers and tanks is reduced. This increases the cost of domestic water heating in the average home by about fifteen to twenty percent. Another negative effect of limescale is that it has damaging effects on household appliances, such as washing machines and dishwashers.

Water softening means extending the life of household appliances and of pipelines. It also contributes to the improved working and longer lifespan of solar heating systems, air conditioning units and many other water-based applications.

Water softeners are specific ion exchangers that are designed to remove ions, which are positively charged. They mainly remove calcium and magnesium ions. These are often referred to as ‘hardness minerals’. Softeners are sometimes also applied to remove iron from the water and are able to remove up to five milligrams per litre of dissolved iron. The softener collects these minerals within its conditioning tank and from time to time flushes them away to the drain. It will replace the calcium and magnesium ions in the water with other ions, for example sodium or potassium. The replacement ions are added to the exchanger reservoir as sodium and potassium salts.

Softeners can operate automatically, semi-automatically or manually. Each type is rated on the amount of hardness it can remove before regeneration is necessary. Most are located under the kitchen sink or near to where the mains water enters the house. The kitchen tap can be not hooked up to the softened water so that untreated drinking water is available.

A good water softener will last many years. Ones that were supplied in the 1980’s may still work, and many need little maintenance apart from filling them with salt occasionally.