The water, which is fit for use by human being is called fresh water. Fresh water is any naturally occurring water. Water in lakes, ponds, etc. is fresh water. NOTE: Freshwater is essential for life. Plants, animals, and humans all need freshwater to survive. We use for drinking water, to irrigate crops, as part of sanitation systems, and in industrial factories, to name a few. Water used up from groundwater, rivers and lakes is replenished by rain and snowfall.

The amount of water that flows through the surface of the earth without getting collected is called run-off. It is very important because the force of the flow of water changes the land patterns by causing erosion and dissolving minerals, and also forming lakes and ponds.