Diageo, one of the world's leading drinks manufacturers, was awarded a five-star rating on June 5.

Since 2003, the Huntingwood factory has reduced its water usage for manufacturing products by 42per cent.

The company credited its management and workforce at Huntingwood for this.

For example, one of Diageo Huntingwood's fitters, John Duncan, has invented a vacuum pump that reduces water use by an estimated 18 million litres a year.

``Ensuring that Diageo's manufacturing sites operate in an environmentally sustainable way is fundamental to our business goals,'' said the company's supply director, Ewan Andrew.

Mr Andrew said the Huntingwood site had also reduced its carbon footprint.

Last year it installed some solar panels, cutting greenhouse-gas emissions by more than 22,000 kilograms.

Ninety-fiveper cent of waste materials at Diageo Australia are recycled.

``Environmental sustainability is an ongoing commitment for Diageo and we'll see a number of other initiatives come to fruition over the next six to 24 months,'' Mr Andrew said.