Water softener, filter or descaler: which one do you need?
A softener is not the answer for every hard-water home. Here is what each option does, what it costs to run and when it pays for itself.
Ion-exchange water softener
A softener swaps calcium and magnesium for sodium using resin and salt. It protects the whole house: boiler, pipes, showers and appliances. It needs a plumber to fit, salt top-ups and a separate unsoftened tap for drinking, because softened water is not recommended for making up baby formula. It makes most sense in very hard areas, in homes with a combi boiler or where scale has already caused repairs.
Jug and tap filters
Jug filters reduce temporary hardness in the water you drink, so tea looks clearer and the kettle scales up more slowly. They do nothing for the shower, the boiler or the washing machine. They are cheap to start with, but cartridges add up over a year.
Scale reducers and magnetic devices
Polyphosphate cartridges fitted before a combi boiler slow scale in the heat exchanger and are often recommended by boiler makers in hard-water areas. Magnetic and electronic devices are cheaper, but independent evidence that they work is weak, so treat claims with care.
Simple descaling
For most homes in moderately hard areas, setting the dishwasher correctly, the right detergent dose and regular descaling with citric acid is enough. It costs a few pounds a year.
How to decide
- Soft or moderately hard water: no softener needed; descale now and then.
- Hard water: descale regularly; consider a scale reducer before a combi boiler.
- Very hard water with scale damage already: get quotes for a softener and compare them with the cost of repairs.