SummaryWater stress index is typically defined as the relationship between total water use and water availability. The closer water use is to water supply, the more likely stress will occur in natural and human systems. This indicator has been used by the United Nations and others. General Information about this IndicatorWhat is it?: This index is used by the global Environmental Protection Index and represents the proportion of an area or region that is over-subscribed. Total water use is divided by water supply during the same period to get an index of “local relative water use”.