Precipitation takes place when water condensation becomes sufficient that water droplets are heavy enough to fall back to the surface of the Earth. Precipitation is a very common phenomenon in the atmosphere of our Earth. This precipitation always comes from clouds. Yet most clouds do not form precipitation.

Surface Runoff is the flow of water that occurs when excess stormwater, meltwater, or other sources flows over the earth's surface. This might occur because soil is saturated to full capacity, because rain arrives more quickly than soil can absorb it, or because impervious areas send their runoff to surrounding soil that cannot absorb all of it.

Groundwater is used for drinking water by more than 50 percent of the people in the United States, including almost everyone who lives in rural areas. The largest use for groundwater is to irrigate crops.

The process of water molecules escaping the surface of the Earth and entering the atmosphere is known as evaporation. Evaporation takes place as molecules of water escape from a collective body of water. This can be a puddle, a lake, a stream, or just a droplet of water.

Transpiration is a continuous process caused by the evaporation of water from leaves of plants and its corresponding uptake from roots in the soil. Transpiration cools plants down and enables mass flow of minerals to where it is needed in the plant. Mass flow is caused by the decrease in hydrostatic (water) pressure in the upper parts of the plants due to the diffusion of water out of stomata in to the atmosphere.

Condensation is the opposite of evaporation. It takes place when water vapour in the air condenses from a gas, back into a liquid form, and leaves the atmosphere, returning to the surface of the Earth.