Recent rain has filled Pykes Creek Reservoir and Melton Reservoir in the past fortnight.
It is the first time in three years that both have filled to capacity, providing welcome relief for farmers, with drier months approaching.
Melton Reservoir has risen from just five per cent capacity in May to full this week. It is flowing into the Werribee River.
Southern Rural Water water supply manager Ed Smith said the increases were welcome for local farmers following two years of below average rainfall.
“The river catchments are wet, the reservoirs have spilled and these flows will provide a good flush through the Werribee River basin,” Mr Smith said.
“The flows will help improve water quality coming into spring and also help offset the forecast drier than average outlook over coming months.”
He also said he expected the recent rain to help irrigators prepare for this year and beyond.
Elsewhere, the Merrimu Reservoir is rising slowly, as it has a smaller catchment to draw from.
It is up to 42 per cent of capacity, an increase from 25 per cent in May.