Water facts: 0.5% of Earth's water is readily available to drink

Every year on 22 March, the world commemorates World Water Day with the aim of stressing the value of water and raising consciousness about the global water crisis.

The day's key focus, according to the UN website, is to "support the achievement of sustainable development goal (SDG) 6: water and sanitation for all by 2030."

The theme of World Water Day 2021 is "Valuing Water" and has been chosen to highlight the value of water in our daily lives. "The value of water is about much more than its price – water has enormous and complex value for our households, food, culture, health, education, economics and the integrity of our natural environment. If we overlook any of these values, we risk mismanaging this finite, irreplaceable resource," the UN website says.

The right to water and sanitation was declared a constitutional right by the United Nations General Assembly in 2010. For personal and domestic use, everybody has the right to adequate, constant, clean, reasonable, physically available, and affordable water.

So for the day that stresses the value of water, here are some quick facts about the worldwide water supply.

• Water occupies about 71 percent of the planet's surface.
• There are 326 million cubic miles of water on the planet.
• The oceans hold 97 percent of the world's water which is way too salty for drinking and growing crops.
• Oceans hold 320 million cubic miles of water.
• Just 3 percent of the world's water is fresh. Of which, 2.5 percent is inaccessible because it is bottled up in glaciers, polar ice caps, the atmosphere, and soil. It is heavily polluted or it is too far under the earth's surface to be extracted at an affordable cost.
• Only 0.5 percent of the world's water is available fresh water.
• If the world's water supply was just 100 litres, our available fresh water supply would be less than 0.003 litre (one-half teaspoon).
• This means each person on the planet can use an average of 8.4 million litres of water.
• This supply is continually collected, purified, and distributed in the natural hydrologic (water) cycle.

Where water is found and the percentage

*Some of this lies too far under the earth's surface to be extracted at an affordable cost. Stats have been taken from the United States Bureau of Reclamation.

If the Earth were a 28 inches in diameter globe 

All of the water on the planet would fill less than one cup.

Only 0.03% of one cup is in rivers and freshwater lakes.

Slightly more than one drop of water would fill all the rivers and lakes.

Sources of freshwater

Groundwater is water that seeps into the ground by porous layers and travels deeper into the ground. It covers pores and cracks in underground rock layers known as aquifers. Some of this water lies too far under the earth's surface to be extracted easily.

Streams, ponds, rivers, wetlands, and reservoirs are examples of surface-water drainage, which is moisture that does not infiltrate into the earth or return to the atmosphere.

The snow that is 4 inches deep contains about the same amount of water as 1/3 inch of rain.