How Much Water Is There On Earth? (Ocean Water, Fresh Water & Drinkable Water)

How Much Water Is There On Earth? - Ocean, Fresh Water & Drinkable Water

A large portion of the Earth’s water is in the ocean.

Fresh water is distributed unequally in much smaller amounts amongst different countries. 

Not all fresh water is drinkable though.

In this guide, we outline the % share of each water type on Earth.

*Note – these numbers are estimates, and are to be used as a general guide only. Also, these number take into consideration the Earth’s surface only. There is also water in the Earth’s atmosphere, in clouds, as water vapour (some estimates put water vapour at 0.001% of the Earth’s water share/distribution), and even in plants and other life.

 

Summary – How Much Water Is There On Earth?

The water on earth can be divided into:

  • About 71% of the world’s surface is covered by water
  • Roughly 96.5% of water on the Earth’s surface is ocean
  • Roughly 2-3% of water is freshwater, and about 1.6% of that is locked up in ice and now
  • 0.36% of freshwater is found underground in aquifers and wells (groundwater)
  • Only about 0.036% of the planet’s total water supply is found in lakes and rivers (surface water)
  • Not all fresh water is accessible for different reasons, and not all fresh water that is accessible is immediately drinkable (due to factors like being being brackish water, or being contaminated). Different cities around the world might get different %’s of their potable and non poatable fresh water from above ground and underground water sources respectively. 
  • Less than 1 percent of the world’s total freshwater supply is readily accessible from the various freshwater sources
  • The % of water available on earth that is ready and available to drink and use, works out to be about 0.007%
  • This number only represents natural water sources though, and not technology such as desalination that can augment water supplies. Perth in Western Australia is an example of a city currently using desalination technology to augment their water supply
  • Read more in this guide specifically about fresh water supplies around the world

 

How Much Of The Earth’s Surface Is Water?

  • About 71% of the world’s surface is covered by water

– water.usgs.gov

 

If water quantities were to be described in spheres, the water distributions are as follows:

  • A sphere of all water on Earth would have a diameter of about 860 miles
  • A sphere of all of Earth’s fresh water would have a diameter of about 169.5 miles 
  • A sphere of all of Earth’s immediately accessible fresh water would have a diameter of 34.9 miles 

– water.usgs.gov

 

How Much Water Is In The Ocean?

  • Of the world’s surface water, about 96.5% is the ocean

– water.usgs.gov

 

  • The average depth of the ocean is several thousand feet (about 1000 metres)

– science.howstuffworks.com

 

This gives us a rough idea of the volume of saltwater on earth.

 

How Much Fresh Water Is There On Earth?

  • About 2-3% percent of the planet’s water is fresh, but 1.6 percent (around 70%) of the planet’s fresh water is locked up in the polar ice caps, snowfields and glaciers
  • 0.36 percent of freshwater is found underground in aquifers and wells (also called groundwater)
  • Only about 0.036 percent of the planet’s total water supply is found in lakes and rivers 

– science.howstuffworks.com

 

Explained another way:

  • 3% of the world’s water is fresh water
  • 69% of the 3% is in glaciers and ice caps
  • 30% of that 3% is in ground water in underground soil and rock crevices
  • 1% of that 3% is in surface water and other sources
  • Of that surface water, 87% is in lakes, 11% in swamps and 2% in rivers

– the71percent.org

The full resource is worth reading as they list some of the places on Earth that hold the highest concentrations (in volume) of fresh water – the world’s fresh water sources  (the71percent.org)

 

The rest of the water on the planet is either floating in the air as clouds and water vapor, or is locked up or contained in plants and animals and living things like humans

There’s also billions of gallons of drinkable water in bottles of water in shops on shelves around the world at any one time.

It’s important to note water is constantly moving on the Earth between the atmosphere, ocean, rivers and streams, snowpacks and ice sheets, and underground. This is known as the hydrologic cycle.

 

Read more about fresh water resources and supplies, how we use them, and what to consider when managing fresh water into the future in this guide.

 

How Much Drinkable Water Is On Earth?

  • Less than 1 percent of the world’s total freshwater supply is readily accessible from the various freshwater sources

– livescience.com

 

  • That’s still thousands of trillions of gallons, but it’s a very small amount compared to all the water available
  • As a % of the total amount of water available on earth that is ready and available to drink and use, that % number works out to be about 0.007 percent

– nationalgeographic.com

 

In other words, when you subtract all the salt water, water trapped in ice/snow and water not physically accessible, you have about 0.007% left to drink, and use for business, agriculture and the community.

Much of that water we get from rivers and lakes – but each country in the world and even different cities withdraw and consume different shares of water from surface water and ground water sources. 

Some of it is not going to be drinking quality – because of water pollution or contaminants, or even because it’s brackish water (too saline).

Some water can be treated or purified to drink (after it’s been tested) at water treatment plants, but some water can’t be.

Water used for agriculture and irrigation may not have to reach the same quality standards as drinking water.

Cities now are even using water from water recycling and water desalination (which are not included in the above estimates and numbers as these are not natural sources of water).

 

Detailed Look At Where Water On Earth Is Located/Distributed By Source

You can look at a detailed table showing global water distribution at:

 

Mdba.gov.au also outlines the following % distributions of Earth’s water:

  • Water Vapour – 0.001%
  • Fresh Water (on the surface – lakes, rivers, etc) – 0.025%
  • Fresh Water (underground) – 0.615%
  • Fresh Water (frozen in ice caps, glaciers, snow) – 2.15%
  • Salt Water (underground) – 0.93%
  • Salt Water (oceans) – 97.2%

 

Countries With The Most Freshwater

  • 6 countries (Brazil, Russia, Canada, Indonesia, China and Colombia) have 50 percent of the world’s freshwater reserves
  • One-third of the world’s population lives in “water-stressed” countries, defined as a country’s ratio of water consumption to water availability. Countries labeled as moderate to high stress consume 20 percent more water than their available supply.

– livescience.com

 

  • Due to geography, climate, engineering, regulation, and competition for resources, some regions seem relatively flush with freshwater, while others face drought and debilitating pollution.
  • In much of the developing world, clean water is either hard to come by or a commodity that requires laborious work or significant currency to obtain

– nationalgeographic.com

 

Will We Have Enough Water In The Future For Human Use?

Read this guide about the availability of freshwater for humans in the future.

 

Sources

1. https://water.usgs.gov/edu/earthhowmuch.html

2. https://science.howstuffworks.com/environmental/earth/geophysics/question157.htm

3. https://www.livescience.com/29673-how-much-water-on-earth.html

4. https://www.nationalgeographic.com/environment/freshwater/freshwater-crisis/

5. https://water.usgs.gov/edu/gallery/global-water-volume.html

6. https://www.bettermeetsreality.com/freshwater-supply-usage-around-the-world-how-much-freshwater-we-have-how-much-we-use-how-we-use-it/

7. https://www.mdba.gov.au/education/resources/water-availability#

8. https://www.the71percent.org/the-worlds-fresh-water-sources/

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