Hard Water

Hard water is a state of water with high mineral content. This is mainly caused by dissolved calcium and magnesium. There are two types of hard water:

• The hardness of water caused by calcium bicarbonate is known as temporary hardness. 

• Whereas hardness associated with other mineral salts is permanent hardness. 

Hardness causes residues in the dishwasher, less foam with detergents and soaps, wearing out of clothes and less water pressure through taps. These are also some of the common signs when it is time to think about softening of water in the home. There are no serious health issues regarding hard water, but it might cause dryness of skin and hair. Temporary hardness can be removed by boiling, but it is difficult to remove permanent hardness. Water softening at home can be done using a water softening system that has a porous plastic resin coated with sodium.

What is Hard Water? – Meaning

Hard water is a state of water with dissolved calcium and magnesium. When hard water is boiled in boilers, deposits of calcium carbonate are formed as plaques which reduce the equipment lifespan considerably. This dissolution of minerals takes place during normal water cycles, and the grade of hardness sometimes depends on the geological area.

How can you detect the hardness of water?

The hardness of water may not be clearly visible. But when we closely observe, we can feel the hardness of the water:

• Stains in sink and tub

• Clothes wearing out easily

• Dull colours of clothes

• White, chalky residue on dishes and pipes

• Dry skin and dry hair

• Less foam with soap

Types of hardness

Hard water can be temporary or permanent. Temporary hardness is caused by carbonates and bicarbonates of calcium and magnesium. But permanent hardness is caused by other salts of calcium and magnesium. Temporary hardness can be solved by boiling. When temporary hard water is boiled, soluble salts are precipitated after it changes to insoluble salts. The permanent hardness of water can be softened using a measured quantity of washing soda.

Water softening methods

• Boiling

• Clark’s process

Ca(HCO3)2 + Ca(OH)2 → 2CaCO3 + 2H2O.

• Calgon method: Calgon reacts with hard water and precipitates with salts, which is easier to remove from water.

• Ion-exchange resins: The unwanted ions in hard water are exchanged with more agreeable ions like sodium ions.

• Washing soda

Hard water problems

We have discussed the signs of hardness. Let us discuss the problems of using hard water. We do not want the water in our daily use make us feel bad. When we have hard water, sulphur present in it might cause a rotten egg smell or a musty odour. Hard water may also have a metallic taste. Hard water causes discolouration and cloudiness. Rusting of iron and steel increases with hard water. In industrial cases, hard water causes corrosion, deterioration of equipment, build-ups in pipes and low flow pressure.

Hard water is formed due to dissolved minerals in the water. It is water with high mineral content. The hardness of water can be temporary or permanent. Hardness is caused by carbonates and bicarbonates of calcium and magnesium. Permanent hardness is caused by other salts of calcium and magnesium.

The methods to remove the hardness of water are:

• Boiling

• Clark’s process

Ca(HCO3)2 + Ca(OH)2 → 2CaCO3 + 2H2O.

• Calgon method: Calgon reacts with hard water and precipitates with salts, which is easier to remove from water.

• Ion-exchange resins: The unwanted ions in hard water are exchanged with more agreeable ions like sodium ions.

• Washing soda

The hardness of water is due to the presence of calcium and magnesium in excess. The hardness of water is conventionally expressed in terms of CaCO3.

Conclusion

Hard water is a state of water with dissolved calcium and magnesium. There are two types of hard water. The hardness of water caused by calcium bicarbonate is known as temporary hardness. This dissolution of minerals takes place during normal water cycles and the grade of hardness sometimes depends on the geological area. Hardness causes the formation of residues in the dishwasher, less foam with detergents and soaps, wearing out of clothes and less water pressure through taps. No serious health issues are involved due to hard water, but it might cause dryness of skin and hair. Temporary hardness can be removed by boiling. Other methods of removing hardness include the Clarks process, Calgon process and ion exchange resin.