Groundwater moves slowly through subsurface rock and sediment and may eventually work its way back to the surface through springs or through streams that interact with the groundwater. It may also be pumped to the surface through water wells for human consumption and irrigation. Surface water in rivers, lakes, and wetlands rejoins the water cycle when it evaporates or transpires into the atmosphere or infiltrates into the ground.

Although over 70% of Earth's surface is covered with water, less than 1% is available for human consumption. Watch this video and discuss methods that can be used to purify and conserve this critical resource. Assess how much water you, your peers, and your family typically use, and think about ways to reduce their water usage.