Everything You Need to Know About Hard Water

Share on facebook
Share on google
Share on twitter
Share on linkedin

What is Hard Water?

Hard water refers to water that contains a lot of minerals which are mainly composed of metal ions such as calcium and magnesium. It is usually brought about when water gets into contact with these minerals or rocks containing them. Such rocks include limestone and chalk.

Water Softening

This refers to the process of making hard water soft by removing the dissolved minerals. This can be done by using a certain substance, device or carrying out a particular process. The aim here is to ensure that calcium and magnesium ions that are responsible for hardness are eliminated.

How to Soften Hard Water

There are various ways of softening hard water. Some are cheap while others are expensive to employ. Such methods include the following.


When hard water is distilled, the nonvolatile salts will automatically be eliminated hence rendering it soft.

Addition of Lime

When calcium hydroxide or lime is added to water, the resultant reaction makes the Calcium ions precipitate hence reducing the hardness of the water.


Boiling is important because it helps to break the bicarbonate ions into carbonate thus removing calcium carbonate from water.

Use of Ion Exchange Resins

This is the process of removing calcium and magnesium ions from hard water by replacing them with potassium and sodium ions. It is done by adding a solution containing sodium or potassium such as sodium or potassium hydroxide.

Use of Chelating Agents

This refers to the use of special ingredients to soften hard water. Such include citric acid and EDTA.

Reverse Osmosis

This is where water molecules are permeated through the membrane thus leaving behind calcium and magnesium ions that are responsible for hardness. The process makes use of hydrostatic pressure working mechanism.

Types of Water Hardness

There are two main types of water hardness:

Temporary Hardness

Just as the name suggests, temporary water hardness is temporary and can, therefore, be removed with ease through boiling. It is normally caused when bicarbonate minerals such as calcium and magnesium bicarbonate dissolve in water. They release calcium and magnesium ions which render water hard. However, when methods such as boiling are employed, the carbonates containing magnesium and calcium ions are precipitated out of the solution.

Permanent Hardness

This refers to the type of hardness that cannot be removed by boiling. It is mainly caused by sulfate ions which may only be removed by using an ion-exchange column or water softener.

Effects of Hard Water

  • Wastage of soap because it causes soap scum instead of lather
  • Formation of scales on plumbing materials which leads to clogging
  • Galvanic corrosion in electrolytes
  • Cloud water appearance in swimming pools called turbid

Classifications of Water

Measurement of Water Hardness

      • Soft
      • Slightly hard
      • Moderately hard
      • Hard
      • Very hard



Measurement of Water Hardness

Hard water is measured by getting the total number of concentration of Calcium and Magnesium ions in moles per liter. This kind of quantification is referred to us instrumental analysis.


In conclusion, hard water has a considerable number of negative impacts. It leads to damage to our equipment, increases the consumption of soap and causes diseases like eczema. Appropriate methods need to be employed to soften it so as to avert the negative consequences. However, hard water has some health benefits because it decreases the solubility of toxic ions such as lead which are readily soluble in soft water.

Additional Resources

Leave a Reply

Your email address will not be published. Required fields are marked *