Water is a precious gift of nature and is a must for life. About 70 percent of our body is made of water. Most of the chemical reactions that keep our bodies working properly require water. Life without water can last for a few days. Even slight dehydration affects the function of our bodies.
Those who do not drink enough water may suffer from headaches, loss of concentration, irritation and tiredness. Mild chronic dehydration is associated with;
-- constipation
-- poor oral health
-- increased risk of stone formation in kidneys
-- increased risk of urinary tract cancer
-- increased risk of fatal coronary heart disease.
Water loses from our body through excretion, respiration and perspiration. Therefore, we need to keep on replacing this loss of water to avoid dehydration. Our bodies obtain water:
-- by drinking - Water is the main ingredient of all beverages but drinking plain water is the best way to replace lost fluid.
-- by eating - Water is present in most foods. Fruit and vegetables have high water contents.
-- as a by-product of chemical reactions within the body.
How much water do we need?
The amount of water we need to drink varies, but on average, a 60 kg adult needs to drink about 2 litres of water every day - roughly 6 to 8 glasses. Water loss from a child's body is proportionally higher, so a 10 kg child would still need to drink about 1 litre a day.
We need to drink more water when the weather is hotter or when we are physically more active to replace additional water loss through perspiration. In extreme circumstances, this could amount to as much as 25 litres a day. Pregnant and breast-feeding women also require additional water to provide for their babies needs. People who are ill (especially those with diarrhoea and vomiting or a fever) will need additional water to replace the fluid that has been lost and to prevent dehydration. Adequate fluid replacement is an essential part of many medical treatments.

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     The average volume of drinking water (litres per day) required
                         to maintain hydration
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                        In average           Moderate             When
                         Conditions          activity        pregnant/
                                              at 25°C   breast-feeding
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Woman                   2.2 litres           4.5 litres     4.8 litres
                                                           (pregnancy)
                                                           5.5. litres
                                                      (breast-feeding)
Man                     2.9 litres           4.5 litres              -
Child (10 years old)    1.0 litres           4.5 litres              -
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Water is also essential for cooking food. The amount we use varies with our diet, but an average of 2 litres per person per day has been suggested.
We also need water to keep our homes and bodies clean. Additional water is required for personal hygiene, including hand washing, food preparation, bathing and laundry.
However, the water supplied in our homes is not clean and pure. A wide variety of chemical, microbial and physical hazards, that could harm our health if they are present at sufficient levels, may contaminate our water. These hazards may arise from a variety of industrial, agricultural and domestic activities.