Water hardness and limescale

In short: Water hardness indicates how much calcium and magnesium are dissolved in the water. Hard water leaves limescale in appliances and affects detergent and dishwasher dosage.

In more detail: In Germany hardness is given in degrees of German hardness (°dH) or mmol/l.

In detail

• Hardness ranges: Soft below 8.4 °dH, medium 8.4 to 14, hard above 14.
• Cause: The water dissolves limestone and gypsum from the ground.
• Limescale deposits: Form on heating in kettle, washing machine, heating element (kaffeemaschine-und-wasserkocher-funktionsweise).
• Descaling: Citric or acetic acid dissolve limescale (ph-wert-saeuren-und-laugen).
• Dishwasher: Salt adjusts the softener (geschirrspueler-funktionsweise).
• Detergent: Dose more with hard water (waschmaschine-funktionsweise).
• Find out the hardness: From the water supplier or with test strips.
• Health: Hard water is harmless; calcium and magnesium are useful.