The Daily Liberal asked Mr McMahon how the council would access its full entitlement of about 4.3 gigalitres (GL) of groundwater a year.

The question was prompted by advice last week from the city's water for the future coordinator and consultant Chris Devitt that the council was conscious of the aquifer's 20GL "safe extraction" annual limit.

Mr Devitt said currently the council was using about 2GL of its groundwater entitlement with other users "taking the rest".

READ ALSO: Worst-case scenario: Dubbo water to run out in early 2021

In a statement responding to this newspaper's questions, Mr McMahon said the council had a groundwater extraction licence which allowed it to use its allocation each year.

"WaterNSW and DPIE (Department of Planning, Industry and Environment) Water manages the allocations and licensing overall for surface and groundwater allocations in NSW," he said.

"While council has traditionally not used its full allocation it is there each year and available for use."

In September Mr McMahon told of the aquifer being under pressure.

"This supply is significantly over allocated and current usage is in excess of the extraction limit for this supply," he said.

The CEO said the council wanted to see "greater regulation of irrigation and private bores".

READ ALSO: Bores to 'spread the load' when council extracts full entitlement

Dubbo is reported to need 6.5GL a year under level four water restrictions, starting November 1.

Mr Devitt, the council's former infrastructure and operations director, said the council needed to launch an expression-of-interest (EOI) process in a bid to buy another 2.2GL of water.

The Upper Macquarie alluvial aquifer runs from Wellington to east of Narromine.

Accessing its full entitlement of groundwater is part of the council's multifaceted plan addressing the possibility of Burrendong Dam being empty by mid-2020.

READ ALSO: No plans for residents to drink effluent yet but trading it is an option