This document defines hardness of water as the property of water to form an insoluble curd with soap instead of lather due to the presence of calcium, magnesium, bicarbonates, sulfates and chlorides. It classifies hardness into temporary and permanent and discusses how hardness is measured in milliequivalents per liter. Hardness levels are classified as soft, moderately hard, hard and very hard. Both advantages like reduced heart disease and disadvantages like economic losses due to scaling are covered. Methods for removing temporary and permanent hardness are also outlined.

1. Hardness of Water
 DEFINITION:
“ The property of water to form an insoluble
curd with soap instead of lather. In other
words it is the soap destroying property due
to the presence of Bicarbonates, Sulphates
and Chlorides of Calcium and Magnesium.”

2. Types of Hardness
A. TEMPORARY HARNESS:
It is due to the presence of Bicarbonates of
Calcium & Magnesium and can be
removed by boiling.
B. PERMANENT HARDNESS:
It is due to the presence of Sulphates,
Nitrates and Chlorides of Calcium &
Magnesium.

3. Measurement of Hardness
 Hardness of water is expressed / measured
in terms of milli equavilant / litre
1 milli-equavilant = 50 mgs.of CaCO3 / litre

4. Classification of Hardness
 Soft water-------------------- = 1 m.Eq. / litre
 Moderately hard water--- = 1-3 m.Eq. / litre
 Hard water----------------- = 3-6 m.Eq. / litre
 Very hard water---- = 6 and > 6 m.Eq. / litre

5. Advantages of Hardness
 Reduced prevalence of,
1.Arteriosclerotic heart disease
2. Degenerative heart disease
3. Sudden death due to Cardiac arrest
4. Hypertension and
5. Tetny

6. Disadvantages
 Are in the form of economic loss of a
community and a country at large such as:
1. More consumption of soap & detergents
2. More consumption of fuel due to scaling
formation in the boilers in industries
3. Discoloration of foods
4. Short life of clothes due to deposition of salts in
fabrics
5. Disturbance of dyeing process
6. High prices of products
7. Decreased life of cisterns and Pipes

7. Removal of Hardness
A. FOR TEMPORARY HARDNESS:
1. Boiling
2. Addition of Lime
B. FOR PERMANENT HARDNESS:
1. Addition of Lime
2. Addition of Sodium Carbonate
3. Base Exchange method / Permutit Process