By Joe Bongiovanni

In ancient times it was once thought that all land masses floated atop an endless body of water and rivers formed from water leaking up through the crust. Our understanding of the hydrological cycle, also known more commonly as the water cycle, has grown immensely since then. The water cycle is the continuous flow of water in the ground, in water bodies, in the air, and everywhere in between. Water is moved great distances across the globe in variations of solid, liquid, and gas states. This relies on the exchange of energy across the system by the change in temperatures from hot to cold and back again. Cold temperatures lead to precipitation and evaporation occurs as they rise. The water cycle is unique to our world and is absolutely essential to life on earth.

Water Filtration and the Water Cycle by Angel Water
While water can be rapidly transported from one end of the planet to the other, the total amount remains constant and can never be increased or decreased. The water cycle continuously replenishes and stores over 332 million cubic miles of water. That’s a lot of water!!! And despite this enormous amount of water on our planet, only slightly more than 3 percent is freshwater and available for human consumption or activities. Most water is diluted with salt and is found in our oceans, seas, & bays. For a more detailed breakdown of water sources, see the table below.

One Estimate of Global Water Distribution
(Numbers are rounded)

Water source

Water volume, in cubic miles

Water volume, in cubic kilometers

Percent of

Percent of
total water

Oceans, Seas, & Bays 321,000,000 1,338,000,000 96.5
Ice caps, Glaciers, & Permanent Snow 5,773,000 24,064,000 68.7 1.74
Groundwater 5,614,000 23,400,000 1.69
    Fresh 2,526,000 10,530,000 30.1   0.76
    Saline 3,088,000 12,870,000   0.93
Soil Moisture 3,959 16,500 0.05 0.001
Ground Ice & Permafrost 71,970 300,000 0.86 0.022
Lakes 42,320 176,400 0.013
    Fresh 21,830 91,000 0.26 0.007
    Saline 20,490 85,400 0.006
Atmosphere 3,095 12,900 0.04 0.001
Swamp Water 2,752 11,470 0.03 0.0008
Rivers 509 2,120 0.006 0.0002
Biological Water 269 1,120 0.003 0.0001
Source: Igor Shiklomanov’s chapter “World fresh water resources” in Peter H. Gleick (editor), 1993, Water in Crisis: A Guide to the World’s Fresh Water Resources (Oxford University Press, New York).


What’s so amazing about the water cycle is the system’s ability clean drinking for millions of years. It is only in the most recent hundreds of years that that deteriorating water quality has become an issue of concern. This cycle naturally purifies water through a variety of processes that take place within. Distillation occurs during evaporation and salt is left behind as water vapor dissolves into the air. Crystallization can be observed naturally when icebergs form with mostly salt-free water. Sedimentation occurs when suspending particles are removed in slow moving streams and rivers. Water Filtration results naturally when it passes through sands, limestone, or small rocks. Other forms of naturally occurring filtration includes Aeration, Oxidation, and Dilution.

Despite all the contamination and pollution we put into a system crucial to our survival, it continues to replenish and recycle the water supply. As good of a job as our planet does of providing us with drinking water, there is only one way to be sure that you have clean and safe drinking water in your household. Call Angel Water today at (847) 382-7800 and find out about how a Home Water Purification System can benefit you!