Hard water is water that has high mineral content (in contrast with "soft water").
Hard drinking water is generally not harmful to one's health, but can pose serious problems in industrial settings, where water hardness is monitored to avoid costly breakdowns in boilers, cooling towers, and other equipment that handles water. In domestic settings, hard water is often indicated by a lack of suds formation when soap is agitated in water. Wherever water hardness is a concern, water softening is commonly used to reduce hard water's adverse effects.
Read more about Hard Water: Sources of Hardness, Effects of Hard Water, Measurement
Famous quotes containing the words hard and/or water:
“One might call habit a moral friction: something that prevents the mind from gliding over things but connects it with them and makes it hard for it to free itself from them.”
—G.C. (Georg Christoph)
“What did it matter where you lay once you were dead? In a dirty sump or in a marble tower on top of a high hill? You were dead, you were sleeping the big sleep, you were not bothered by things like that. Oil and water were the same as wind and air to you.”
—Raymond Chandler (1888–1959)