The sources

The Water Needed to Have the Dutch Drink Coffee

Chapagain, A.K. and Hoekstra, A.Y · UNESCO-IHE / Water Footprint Network · 2003

Roughly 140 litres per 125 ml cup.

Cited in

Chapagain, A.K. and Hoekstra, A.Y. The Water Needed to Have the Dutch Drink Coffee. UNESCO-IHE / Water Footprint Network, 2003. (Roughly 140 litres per 125 ml cup.)