Different source of water

we know that water is a main essential compound for living organism. The water which is used by living beings occurs from different sources of Water, basically there are two main sources of water which are follows-
1) Surface water--Water which is available from the earth surface is called surface water. It is generally clear and colourless and acidic in nature due to dissolved CO2 and organic matter. Surface water includes following types of water-

(a) Rain Water- Rainwater is obtained of evaporation from surface water, it is the purest form of natural water, during its downward Journey through the atmosphere it dissolved a considerable amount of industrial gases (like CO2 So2, No2 etc.) Rainwater is expensive to collect and irregular in supply.

(b) River Water- River water contain dissolved minerals like chlorides, sulphates bicarbonates of sodium magnesium, calcium and iron water from these sources now over the surface of land. The composition ofriver water not constant. In river water the greater is the amount of dissolved impurities. The amount of dissolved impurities depends on its contact of the soil.

(c) Lake Water-Lake water has more constant chemical composition. It has high quantity of organic matter but lesser amount of dissolved minerals. The chemical composition of lake water is constant.

(d) Sea Water- It is the most impure form of the natural water, because sea water contains various types of impurities. we know that all rivers join sea and throw in the impurities carried by them. There are many salts present in sea water. Bicarbonates of potassium magnesium and calcium and other harmful compounds  present in sea water.

2) Underground Water- Some part of rainwater which is reaches the inner surface of earth is called underground water mainly spring water and well water.
Generally spring and well water is clear in appearance due to the mering action of the soil, but this type of water contain moreover dissolved salts. Thus, water available from these sources contains high more hardness and organic impurities.