What is hardness in water?

The hardness of water is due to the presence of soluble bicarbonates, chlorides and sulfates of calcium and magnesium. Water which does not give lather with soap is hard water.

Water is the most important compound that is needed for the survival of life on earth. Water is present in the oceans, rivers, ponds, lakes, glaciers, etc. Rainwater is considered pure water because it does not contain any salt dissolved in it thought there are dissolved gases present.

Water can be classified as hard water and soft water.

  • Soft water: It lathers with soap. Water which is obtained from the rains is soft water. This water is suitable for household purposes for example laundry and cleaning.
  • Hard water: It is known as hard water because of the presence of salts of calcium and magnesium. Hard water does not lather with soap but instead forms a precipitate. It causes stains and clogs shower heads and faucets.

Check difference between hard water and soft water

What is Hard Water?

Hard water has high mineral content. It is formed when water percolates through the deposits of chalk and limestone which are made up of magnesium and calcium carbonates. It does not lather with soap, so it is not suitable for laundry purposes.

Hard water is safe to drink but using over a long interval of time can lead to many problems like:

  • Strains in skin
  • Water appliances work harder resulting in higher water bills
  • Spots appear on clothes and linens

Types of Hardness of Water

The hardness of water can be classified into two types:

  • Temporary Hardness 
  • Permanent Hardness

Temporary Hardness of Water:

The presence of magnesium and calcium carbonates in water makes it temporarily hard. In this case, the hardness in water can be removed by boiling the water.

When we boil water the soluble salts of Mg(HCO3)2 is converted to Mg(OH)2 which is insoluble and hence gets precipitated and is removed. After filtration, the water we get is soft water.

Permanent Hardness of Water:

When the soluble salts of magnesium and calcium are present in the form of chlorides and sulphides in water, we call it permanent hardness because this hardness cannot be removed by boiling.

We can remove this hardness by treating the water with washing soda. Insoluble carbonates are formed when washing soda reacts with the sulphide and chloride salts of magnesium and calcium and thus, hard water is converted to soft water.


Harmful Effects of Hard Water

Some of the most common signs of hard water include:

  • Linens and clothes look dull and feel rough.
  • Ugly stains on white porcelain and scale build-up on faucets
  • Low water pressure from showers due to clogged pipes.
  • Chalky, white residue or spots appear on dishes.
  • Strains appearing in the shower.

7 easy ways to resolve hard water issues