A view that Adelaide should be placed under permanent all-year-round water restrictions.

A leading NSW ecologist Professor Richard Kingsford claims the city’s water supply is threatened by the city’s population and productivity growth.

There has been higher than average rainfall in the Mount Lofty Ranges and Adelaide Plains this winter, but the 9 reservoirs that supply Adelaide's water - along with the River Murray - are on average 55% full.

Professor Kingsford says the desal plant does provide another option in addition to his theory of a return to permanent water bans.