This metric is loosely based on the GRI Standards 303 Water and Effluents, which includes the following reporting recommendations:

2.2 The reporting organization should report the following additional information: 2.2.1 A breakdown of total water withdrawal in megaliters by withdrawal source categories listed in Disclosure 303-3, at each facility in areas with water stress; 2.2.2 Total water withdrawal in megaliters by suppliers with significant water-related impacts in areas with water stress.

This metric is for recording the volume of water withdrawn from water stressed regions.

This other metric is for recording water use from water stressed areas as a percentage of total consumption. Only one of these is required for a company in a given year, assuming the total water consumption is also available the other one can be calculated.