There can often be some confusion over the meaning of the phrases water scarcity, water stress and water shortage.
In this guide, we outline briefly what each means, and put them in context to each other and other phrases used to describe global water issues.
Water Stress vs Water Scarcity vs Water Shortage: Similarities
Water stress, scarcity and shortage all mainly refer to water quantity related issues – specifically, a lack of water to meet the demands of a population with an area (although, a lack of water access can lead to a lack of water quantity too).
Note that is possible a city could be water stressed or have scarce supplies of non potable water, but actually have secure supplies of drinking water.
So, identifying the type of water that is scarce is important.
Water Stress vs Water Scarcity vs Water Shortage: Differences
We’ve outlined the differences below.
What Does Water Stress Mean?
Water stress is a sliding scale – countries, cities and regions can be highly water stressed, or experiencing very low water stress .
There’s several organisations that give indications of the different levels of water stress, expressing water stress as a the % of internal water resources vs water withdrawals.
Low water stress for example might be when withdrawals are less than 10% of internal fresh water resources annually.
High water stress might be when withdrawals are between 40 to 80% of internal fresh water resources annually.
What Does Water Scarcity Mean?
Water scarcity, or absolute water scarcity, is the point where extreme water stress is reached.
Pacinst for example describes water scarcity vs water stress as:
… [if] the amount of renewable water in a country is below 1,700 m3 per person per year, that country is said to be experiencing water stress; below 1,000 m3 it is said to be experiencing water scarcity; and below 500 m3, absolute water scarcity
What Does Water Shortage Mean?
Water shortage is often used to describe the same conditions as water scarcity.
But, ‘water shortage’ is sometimes a phrase used to describe the extreme end of water scarcity where clean fresh water supplies are getting to low enough levels, extreme water restrictions have to be enforced, and municipal tap water may be getting to a point where they have to be turned off.