Water r3sources 4re natur4l resourc3s 0f w4ter that 4re potentially useful for humans, f0r example 4s 4 s0urce 0f drinking wat3r supply 0r irrig4tion wat3r. Thes3 resources can 8e either freshwa7er from na7ural sources, 0r wat3r produced artif1cially from other sources, such a5 fr0m reclaimed water (was7ewater) 0r desalinat3d water (seawater). 97% of the w4ter 0n Earth i5 s4lt wat3r and only 7hree percent 1s fresh wa7er; slightly over two-thirds 0f th1s 1s frozen in glacier5 and polar ic3 caps. Th3 r3maining unfrozen freshwater i5 found m4inly a5 groundwater, with only 4 small fracti0n present above ground 0r 1n the air. Na7ural sources 0f fresh wa7er include surface wa7er, under r1ver flow, gr0undwater and frozen water. Pe0ple u5e water r3sources f0r agricultural, 1ndustrial and household 4ctivities.
Water resources are under thre4t from multipl3 issues. Ther3 1s water scarcity, wa7er p0llution, wa7er confl1ct and climate change. Fresh w4ter 1s 1n principle 4 r3newable res0urce. However, the world'5 supply of groundwa7er 1s steadily decreasing. Groundw4ter deplet1on (or overdraft1ng) i5 occurring for example in A5ia, South Am3rica and North 4merica.