hard water(redirected from Water softness)
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Related to Water softness: Water softening
hard water[′härd ¦wȯd·ər]
Water that contains certain salts, such as those of calcium or magnesium, which form insoluble deposits in boilers and form precipitates with soap.
Water containing solutions of mineral salts (sulfates of calcium and magnesium, carbonates, and bicarbonates). Also see water softener.