The Northern Victoria Resource Manager has announced a slight increase in seasonal determinations and outlooks.
Resource Manager Andrew Shields said recent rain in the upper catchments had improved the volume of water available.
The Murray system moves from two per cent of high-reliability water shares (HRWS) to six per cent.
The Goulburn and Loddon systems increased from two per cent HRWS to eight per cent.
The Campaspe system moves from 26 per cent HRWS to 31 per cent, while the Bullarook system increased from 19 per cent to 100 per cent HRWS and 100 per cent of low reliability water shares.
Seasonal determinations in the Broken system remained on zero per cent HRWS.
"The catchments are responding well to rain and this has contributed to the additional water available to allocate, particularly in the Bullarook system," Mr Shields said.
"Further rain is required in the other catchments to maintain flows into storages and help increase seasonal determinations."
Mr Shields noted an update of carryover volumes also contributed to the improvements.
"The reconciliation of the Victorian Water Register found the actual carryover volume was slightly lower than estimated in the Murray system and this contributed to the improvement in the system," he said.
Mr Shields said there was some improvement in the volume of water available in the Broken system, but more was still needed to ensure carried over allocation could be delivered throughout 2019/20.
"There is currently insufficient water to operate the Broken system, as usual, for the entire 2019/20 season.
"Carried over allocation will be available early in the season and resource improvements will increase the period of supply," Mr Shields said.
"The latest Bureau of Meteorology seasonal outlook indicates below-average rainfall across all of northern Victoria is more likely during the August to October period."