Water scarcity is a measure of the available volume of water compared to the water volume needs of humans and nature. Greater water scarcity means less water is available. It is similar to, but not strictly the same concept as Water stress. A water scarce condition may be natural (and not necessarily ‘bad’), for example in arid environments. A water stress condition is when significantly less water is available than for the natural condition for a given location.
It is important to distinguish between physical and economic water scarcity. Physical water scarcity is when there is insufficient water naturally available in water bodies and from precipitation. A water stressed condition may arise from a natural reduction in water availability or due to prolonged over-abstraction. Economic water scarcity is where water is naturally abundant but where humans have insufficient or no piped supply due to government poverty, underinvestment or mismanagement.
