Water masses at the Earth's surface

reservoir volume (in millions of cubic kilometres) percent of total

oceans 1,370.0 97.25

ice caps and glaciers 29.0 2.05

deep groundwater* (750–4,000 metres) 5.3 0.38

shallow groundwater (less than 750 metres) 4.2 0.30

lakes 0.125 0.01

soil moisture 0.065 0.005

atmosphere** 0.013 0.001

rivers 0.0017 0.0001

biosphere 0.0006 0.00004

total 1,408. 7 100

*The total interstitial water in the pores of sediments is on the order of 50×10⁶ to 300×10⁶ km³.

**As liquid equivalent of water vapour.

Source: Adapted from Elizabeth Kay Berner and Robert A. Berner, The Global Water Cycle: Geochemistry and Environment, copyright 1987, Table 2.1, p. 13. Reproduced by permission of Prentice Hall, Inc., Englewood Cliffs, N.J.