THE French boss of the troubled Wonthaggi desalination plant has admitted that the plant is too big for Melbourne's water needs.
Suez Environment chief executive Jean-Louis Chaussade told the Herald Sun the size of the plant was based on unrealistic rainfall expectations.
"The design was done to provide water to the full city of Melbourne in case of no rain during one year - which was not realistic ... The details why it was 150GL per year, I don't know," he said.
"The design is not mine. I am answering what my customer is asking me to build."
The Wonthaggi plant is able to produce 150GL - or 150 billion litres of water - every year if required.
This makes it three times the size of the 45GL-a-year Gold Coast plant and 65 per cent bigger than Sydney's 91GL-a-year Kurnell desalination plant.
Mr Chaussade was in Australia last week touring the desalination plant, which is now operational.
He runs French water company Suez Environment, a major shareholder in the AquaSure consortium building and operating the Wonthaggi plant.
The plant, which will cost Victorians $24 billion over 28 years through higher water bills, is expected to be signed off in February - eight months past an extended deadline.
But Mr Chaussade said the project was a "showcase" that would drought-proof Victoria.
Mr Chaussade's company is suing the State Government for $1 billion to reclaim losses from the job.
He said Victorians complaining about the cost of the plant would appreciate it during the next drought.
Australian Bureau of Statistics figures, released last week, show Victorians used 19 per cent less water in 2011 than a year earlier.
Storages are now 81.3 per cent full after several years' improved rainfall.
Read more on the Herald Sun.