enthärtet

Enthärtet is the past participle of the German verb enthärten, meaning to soften or remove hardness. In general usage it refers to liquids, especially water, whose hardness has been reduced by removing calcium and magnesium ions. The term is common in water treatment and may also be applied to other substances.

In water treatment, enthärtung aims to prevent scale formation, improve cleaning efficiency, and influence taste and feel. The most frequent methods are ion exchange (calcium and magnesium ions are exchanged for sodium or potassium ions), lime-soda softening (precipitation of hardness ions as carbonates), and membrane processes such as reverse osmosis or nanofiltration. Electrochemical softening is another approach used in some facilities.

Applications and effects include reduced limescale deposits, longer life for boilers and pipelines, and lower maintenance costs. For consumers, softened water can improve detergent performance and appliance efficiency, but it may also remove minerals considered beneficial and can alter taste and electrical conductivity. In some cases, excessive softening raises concerns about corrosion in pipes and fixtures if protective measures are not maintained.

Other uses of the term may refer to softening of other liquids or materials, though water remains the primary domain. In aquaristics and brewing, controlling water hardness is important, and enthärtet describes water with lower carbonate hardness (KH) and total hardness (GH).

See also: Härte (Wasser), Enthärtung, Ionenaustausch, Umkehrosmose.