If a tonne of corn is grown in Illinois but consumed in China, is the water used to grow the corn used by the farmer in Illinois or by the consumer in China? This may come across as a philosophical or polemical question, but in an increasingly globalized world, answering this fundamental attribution question is of critical importance for addressing the issue of water resources sustainability. Two major frameworks – the freshwater planetary boundary and the water footprint – have emerged over the past decade to advance our understanding of the sustainability of global freshwater resources. The freshwater planetary boundary quantifies the volume of ‘blue’ water resources that humanity can withdraw and still remain within a presumed, safe ecological operating space.