Water use has become an important issue locally and globally. There is increasing competition between agricultural, industrial, domestic and environmental sectors. Concurrent with this increase in competition, there has been increasing public debate about water and environmental issues. This imposes additional pressure on irrigators, including cotton growers, to be accountable for the way water is used. Even without these external pressures, water use efficiency (WUE) is a key issue for producers. If water is a limiting resource, optimising production per unit of available water is clearly an important component of maximising returns. Further, efficiencies in water use may indicate losses from the system which can cause additional difficulties on the property: excessive rim-off leading to erosion, seepage leading to localised ground water rise and possibly salinisation. To assess the current water use efficiency within the cotton industry we calculated water use efficiency at the crop and the farm level using producers' historical water management data. A whole farm water use efficiency was calculated and then two components of this: the efficiency with which water was supplied to the crop (irrigation efficiency) and the efficiency with which the crop converted the water it actually used into lint(crop water use efficiency). Our results indicate significant opportunities for improving water use. Using this simple technique, producers can assess their own water use efficiency and compare their performance to others in their area or to industry benchmarks.