Filter jug or descaler for hard water?

Hard water is safe; the scale is the nuisance

The Drinking Water Inspectorate says UK drinking water rules set no standard for hardness, and Thames Water says hard water is not considered harmful. The problem is scale: deposits of calcium and magnesium that build up on heating elements, shorten their life and make appliances less efficient, in the DWI's words.

Thames Water also suggests a steel scale collector in the kettle and emptying the kettle when it will not be used for a while.

Using a filter jug well

Brita says to replace a MAXTRA PRO cartridge at least every four weeks, which is about 150 litres at standard hardness, and to run two fills through a new one and pour them away. Keep filtered water somewhere cool, such as the fridge, and use it within a day.

For hard and very hard water, Brita recommends its Limescale Expert cartridge, which it says reduces limescale 50% more than its Pure Performance cartridge. The DWI warns that a cartridge left too long can become a breeding ground for bacteria and leach what it removed back into the water.

Descaling safely, and the whole-house option

Ecozone's method is to half-fill the kettle, boil it, add one sachet, wait 30 minutes and rinse several times. It warns never to boil the solution and to check the appliance manual first.

Neither product treats the boiler or the shower. The DWI says a softener fitted just before the hot water tank or boiler is the economical way to prevent scale there, but the kitchen tap used for drinking should not be softened, because most softeners replace hardness with sodium.