Adelaide's under-used desalination plant could be used to help the Murray River next year.

A new deal struck between the South Australian Government and the Federal Government includes a $2 million study to determine how the plant could be used to reduce Adelaide's reliance on river water.

“In reality, Adelaide's desalination plant is ready to go,” SA Water Minister David Speirs said.

“This plan could be in place sometime in 2019.

“It is our view that the plant has the capacity to offset River Murray take and, as such, we need to thoroughly study this.”

The Federal Government is looking for support to ensure the Murray-Darling Basin Plan can be delivered in full.

Mr Speirs has previously described the $1.8 billion desalination plant as a huge financial burden.

He says the Federal Government will help cover the operating costs if production was to increase.

“SA will not agree to the desalination plant being used if it leads to higher water bills,” Mr Speirs said.

“Any additional water produced will have to be supported by Commonwealth funding.

“[After the study] we will negotiate a funding package from the Commonwealth to support any additional water produced by the plant.”