It is time West Australians "got over" their fear of drinking recycled water, Nationals leader Brendon Grylls said today.

Mr Grylls said the government's controversial decision to pump treated waste water into the Gnangara Mound aquifer was necessary to sustain Perth's water supplies.

The Centre for Water Research has predicted Perth's drinking water supplies from dams will run out by the end of next summer.

The recycled water could be released into the main supply for public consumption within 18 months, with the city's dams on the verge of running dry.

"Some people are nervous about recycled water being used in Western Australia," he said.