What is "hard water"

Hard \Hard\ (h[aum]rd), a. [Compar. Harder (-[~e]r); superl. Hardest.] [OE. hard, heard, AS. heard; akin to OS. & D. hard, G. hart, OHG. herti, harti, Icel. har[eth]r, Dan. haard, Sw. h[*a]rd, Goth. hardus, Gr. kraty`s strong, ka`rtos, kra`tos, strength, and also to E. -ard, as in coward, drunkard, -crat, -cracy in autocrat, democracy; cf. Skr. kratu strength, k[.r] to do, make. Cf. Hardy.]

1. Not easily penetrated, cut, or separated into parts; not yielding to pressure; firm; solid; compact; -- applied to material bodies, and opposed to soft; as, hard wood; hard flesh; a hard apple.

2. Difficult, mentally or judicially; not easily apprehended, decided, or resolved; as a hard problem.

   The hard causes they brought unto Moses.
   --Ex. xviii. 26.

   In which are some things hard to be understood.
   --2 Peter iii. 16.

3. Difficult to accomplish; full of obstacles; laborious; fatiguing; arduous; as, a hard task; a disease hard to cure.

4. Difficult to resist or control; powerful.

   The stag was too hard for the horse.
   --L'Estrange.

   A power which will be always too hard for them.
   --Addison.

5. Difficult to bear or endure; not easy to put up with or consent to; hence, severe; rigorous; oppressive; distressing; unjust; grasping; as, a hard lot; hard times; hard fare; a hard winter; hard conditions or terms.

   I never could drive a hard bargain.
   --Burke.

6. Difficult to please or influence; stern; unyielding; obdurate; unsympathetic; unfeeling; cruel; as, a hard master; a hard heart; hard words; a hard character.

7. Not easy or agreeable to the taste; harsh; stiff; rigid; ungraceful; repelling; as, a hard style.

   Figures harder than even the marble itself.
   --Dryden.

8. Rough; acid; sour, as liquors; as, hard cider.

9. (Pron.) Abrupt or explosive in utterance; not aspirated, sibilated, or pronounced with a gradual change of the organs from one position to another; -- said of certain consonants, as c in came, and g in go, as distinguished from the same letters in center, general, etc.

10. Wanting softness or smoothness of utterance; harsh; as, a hard tone.

11. (Painting)

    1. Rigid in the drawing or distribution of the figures; formal; lacking grace of composition.

    2. Having disagreeable and abrupt contrasts in the coloring or light and shade.

       Hard cancer, Hard case, etc. See under Cancer, Case, etc.

       Hard clam, or Hard-shelled clam (Zo["o]l.), the quahog.

       Hard coal, anthracite, as distinguished from bituminous coal ( soft coal).

       Hard and fast. (Naut.) See under Fast.

       Hard finish (Arch.), a smooth finishing coat of hard fine plaster applied to the surface of rough plastering.

       Hard lines, hardship; difficult conditions.

       Hard money, coin or specie, as distinguished from paper money.

       Hard oyster (Zo["o]l.), the northern native oyster. [Local, U. S.]

       Hard pan, the hard stratum of earth lying beneath the soil; hence, figuratively, the firm, substantial, fundamental part or quality of anything; as, the hard pan of character, of a matter in dispute, etc. See Pan.

       Hard rubber. See under Rubber.

       Hard solder. See under Solder.

       Hard water, water, which contains lime or some mineral substance rendering it unfit for washing. See Hardness, 3.

       Hard wood, wood of a solid or hard texture; as walnut, oak, ash, box, and the like, in distinction from pine, poplar, hemlock, etc.

       In hard condition, in excellent condition for racing; having firm muscles; -- said of race horses.

       Syn: Solid; arduous; powerful; trying; unyielding; stubborn; stern; flinty; unfeeling; harsh; difficult; severe; obdurate; rigid. See Solid, and Arduous.

Water \Wa"ter\ (w[add]"t[~e]r), n. [AS. w[ae]ter; akin to OS. watar, OFries. wetir, weter, LG. & D. water, G. wasser, OHG. wazzar, Icel. vatn, Sw. vatten, Dan. vand, Goth. wat[=o], O. Slav. & Russ. voda, Gr. 'y`dwr, Skr. udan water, ud to wet, and perhaps to L. unda wave. [root]137. Cf. Dropsy, Hydra, Otter, Wet, Whisky.]

1. The fluid which descends from the clouds in rain, and which forms rivers, lakes, seas, etc. ``We will drink water.''
   --Shak. ``Powers of fire, air, water, and earth.''
   --Milton.

   Note: Pure water consists of hydrogen and oxygen, H2O, and is a colorless, odorless, tasteless, transparent liquid, which is very slightly compressible. At its maximum density, 39[deg] Fahr. or 4[deg] C., it is the standard for specific gravities, one cubic centimeter weighing one gram. It freezes at 32[deg] Fahr. or 0[deg] C. and boils at 212[deg] Fahr. or 100[deg] C. (see Ice, Steam). It is the most important natural solvent, and is frequently impregnated with foreign matter which is mostly removed by distillation; hence, rain water is nearly pure. It is an important ingredient in the tissue of animals and plants, the human body containing about two thirds its weight of water.

2. A body of water, standing or flowing; a lake, river, or other collection of water.

   Remembering he had passed over a small water a poor scholar when first coming to the university, he kneeled.
   --Fuller.

3. Any liquid secretion, humor, or the like, resembling water; esp., the urine.

4. (Pharm.) A solution in water of a gaseous or readily volatile substance; as, ammonia water.
   --U. S. Pharm.

5. The limpidity and luster of a precious stone, especially a diamond; as, a diamond of the first water, that is, perfectly pure and transparent. Hence, of the first water, that is, of the first excellence.

6. A wavy, lustrous pattern or decoration such as is imparted to linen, silk, metals, etc. See Water, v. t., 3, Damask, v. t., and Damaskeen.

7. An addition to the shares representing the capital of a stock company so that the aggregate par value of the shares is increased while their value for investment is diminished, or ``diluted.'' [Brokers' Cant] Note: Water is often used adjectively and in the formation of many self-explaining compounds; as, water drainage; water gauge, or water-gauge; waterfowl, water-fowl, or water fowl; water-beaten; water-borne, water-circled, water-girdled, water-rocked, etc. Hard water. See under Hard. Inch of water, a unit of measure of quantity of water, being the quantity which will flow through an orifice one inch square, or a circular orifice one inch in diameter, in a vertical surface, under a stated constant head; also called miner's inch, and water inch. The shape of the orifice and the head vary in different localities. In the Western United States, for hydraulic mining, the standard aperture is square and the head from 4 to 9 inches above its center. In Europe, for experimental hydraulics, the orifice is usually round and the head from 1/2 of an inch to 1 inch above its top. Mineral water, waters which are so impregnated with foreign ingredients, such as gaseous, sulphureous, and saline substances, as to give them medicinal properties, or a particular flavor or temperature. Soft water, water not impregnated with lime or mineral salts. To hold water. See under Hold, v. t. To keep one's head above water, to keep afloat; fig., to avoid failure or sinking in the struggles of life. To make water.

   1. To pass urine.
      --Swift.

   2. (Naut.) To admit water; to leak.

      Water of crystallization (Chem.), the water combined with many salts in their crystalline form. This water is loosely, but, nevertheless, chemically, combined, for it is held in fixed and definite amount for each substance containing it. Thus, while pure copper sulphate, CuSO4, is a white amorphous substance, blue vitriol, the crystallized form, CuSO4.5H2O, contains five molecules of water of crystallization.

      Water on the brain (Med.), hydrocephalus.

      Water on the chest (Med.), hydrothorax.

      Note: Other phrases, in which water occurs as the first element, will be found in alphabetical order in the Vocabulary.

n. (context chemistry English) Water with a high concentration of dissolved minerals, especially calcium, making it difficult to lather with soap.

n. water that contains salts (as calcium and magnesium ions) that limit the formation of lather with soap

Hard water is water that has high mineral content (in contrast with " soft water"). Hard water is formed when water percolates through deposits of limestone and chalk which are largely made up of calcium and magnesium carbonates.

Hard drinking water may have moderate health benefits, 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, and by the formation of limescale in kettles and water heaters. Wherever water hardness is a concern, water softening is commonly used to reduce hard water's adverse effects.