What are the two main sources of water for human use?

The two main sources of water for human use are groundwater and surface water. Groundwater is the water that is stored beneath the Earth's surface, filling the pore spaces in soil and rock formations. It is accessed through wells and is vital for irrigation and drinking water supply in many communities, especially in arid regions.

Surface water refers to water that is found in rivers, lakes, and reservoirs on the Earth's surface. This source is critical for both agricultural practices and direct human consumption. It is replenished by rainfall and runoff, making it an essential part of the hydrological cycle.

This combination of groundwater and surface water provides the majority of water used for municipal, agricultural, and industrial purposes. Other options, while they do involve water sources, either provide limited water supply (like desalination, which is used less frequently and is more energy-intensive) or are more indirect and not typically categorized as primary sources of water for human consumption (like atmospheric moisture and glaciers).