Why is it necessary to conserve water?

It is necessary to conserve water because

1. There is uncertainty in rainfall and distribution of water is uneven.
2. There is over-exploitation and excessive use of water.
3. Contamination of water due to pollution, use of pesticides and fertilizer.
4. There is scarcity of water due to large and growing population.
5. Increasing industrialization and rapid urbanization is exerting pressure on water resources.