What is groundwater?

• A. Water above the surface in lakes
• B. Water that evaporates
• C. Water below the Earth's surface, often flowing through aquifers
• D. Water in clouds

Answer: (C)

Groundwater is water that resides underground in the pore spaces of soil and in fractures of rock, filling and moving through underground layers called aquifers. These aquifers store and transmit water, and groundwater can slowly flow through them, eventually discharging into springs, rivers, wetlands, or being pumped up through wells. This description—water beneath the Earth’s surface, often moving through aquifers—best captures both the location and the way groundwater behaves. It’s distinct from surface water, which sits on the surface in lakes and streams, from water that is evaporating into water vapor, and from water already in clouds in the atmosphere. Groundwater is a key source of drinking water for many communities and is a focus of protection under the Safe Drinking Water Act to keep it clean and safe for use.