ACT dams are 100 per cent full for the first time in more than a decade.
The capital region has already received its best spring rain in 27 years and the rain just keeps on coming.
About 90 millimetres of rain fell across Canberra overnight and more heavy falls are forecast.
2010 is already Canberra's wettest year since 1974.
The Territory's combined dam level is now at 100 per cent, after Googong Dam reached capacity on Friday.
"All of the mountain dams are at 100 per cent and are all overflowing," said ACTEW managing director Mark Sullivan.
Mr Sullivan says it the best position the dams have been in since 1998.
"All of the water that comes out of the mountain dams - and there's a hell of a lot of water coming down the mountains - flows into the Cotter river and from the Cotter River it flows into the Murrumbidgee River and it goes into the Murray-Darling Basin," he said.
"If Googong goes over the top it flows down the Queanbeyan River ... it then flows down the Molonglo River through Lake Burley Griffin across Scrivener down the Molonglo into the Murrumbidgee and into the Murray-Darling Basin.
"The water that leaves Canberra is great for the Murray-Darling Basin."
