hard water

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hard water

- That which contains large amounts of minerals.
See also related terms for minerals.

Hard water

Water that contains an appreciable amount of dissolved salts of calcium and magnesium. Such salts interfere with the action of soap. In the early days of the twentieth century, most rural water came from wells, and most of it was hard. Indeed, in some places, it was reputed to be so hard that a rock dropped into the well would bounce when it hit the water. Slight amounts of dissolved material in drinking water were often preferred because of the taste, but soft water was preferred for washing hair and clothes.
ThesaurusAntonymsRelated WordsSynonymsLegend:
Noun1.hard water - water that contains mineral salts (as calcium and magnesium ions) that limit the formation of lather with soap
H2O, water - binary compound that occurs at room temperature as a clear colorless odorless tasteless liquid; freezes into ice below 0 degrees centigrade and boils above 100 degrees centigrade; widely used as a solvent
soft water - water that is not hard (does not contain mineral salts that interfere with the formation of lather with soap)
References in periodicals archive ?
Aiming at concluding about the most suitable method to predict Fernana's water character, we applied Langelier saturation index LSI, Larson ration LR, Ryznar stability index RSI, the modified Langelier saturation index MLSI.
Lorenzo Cremaschi: 1) The Langelier Saturation Index (LSI) is defined as LSI = pH - [pH.sub.s].
Because Willmar's water is supersaturated with respect to calcium carbonate solubility (has a positive Langelier Saturation Index), any increase in pH above that currently maintained in the finished water (8.1) is likely to initiate precipitation in the mains.