Headline figures from suppliers on cutting water use are "almost irrelevant" because the impact on local resources are of much greater concern than overall savings.

That was the view of SAB Miller sustainable development chief Andy Wales, as he urged the industry to adopt a local focus rather than simply deal in statistics over water use.

Speaking at a PwC biodiversity briefing in London, Wales said: "Big financial numbers are attached so demonstrating the business case for carbon reduction is straightforward but water has less of a specific payback."

Suppliers should understand "it may be difficult to grow business in the future in a particular place because no more ­water is available".

SAB Miller vowed to cut water use by 25% per hectolitre of beer by 2015 on 2008 levels. Last year, it set up Water Futures with WWF to promote better global water management.