What Do the Colours of a Water Footprint Mean?

The water footprint framework splits freshwater use into three colour-coded components. Each one measures something different, and all three together give a full picture of how water is consumed and how its quality is affected across the production of a good or service.

Blue water footprint

Blue water covers the total volume of surface and groundwater freshwater needed to produce a good. This is the category people usually have in mind when they talk about freshwater in the traditional sense: the water drawn from rivers, lakes, reservoirs, and aquifers.

Green water footprint

Green water covers the total volume of rainwater used in producing a good, typically through crop growth. The rainwater counted in this category does not disappear and does not enter the groundwater system. It is stored in the soil, or on the soil surface, long enough to be taken up by plants. Because rainfall patterns drive both the supply and the demand for green water, any green-water assessment needs to take local climate change and variability into account.

Grey water footprint

Grey water is an indicator of pollution. It measures the volume of freshwater needed to assimilate a given pollutant load and bring the receiving water back to agreed quality standards. For that reason the grey-water figure is closely tied to population growth and to industrial growth, both of which drive the pollutant loads the category tracks.

Sistem Patent Kalite helps organisations calculate each of the three components in a way that follows the ISO 14046 methodology, with the results prepared for third-party verification.