Central Highlands Water rejected the request for water from the Gong Gong Reservoir at Tuesday's board meeting.

Chairman John Barnes said CHW could not satisfy the council's request.

"The board doesn't believe it can meet the request at this stage, but we're willing to review it at a later date if we get some rain," Mr Barnes said.

"Ballarat has only just gone from Stage Three to Stage Two water restrictions.

"We would love to put water in the lake, but we aren't prepared to put good drinking water in jeopardy at this time."

Water from the Gong has historically been used to top up the lake in times of need, but that option has dried up in the past three years due to ongoing water restrictions.

But Ballarat City Council's chief executive officer Richard Hancock had been hopeful that CHW would agree to the one-off request in light of the lake's current dire situation.

"Our argument is water restrictions in Ballarat have now eased, we haven't drawn on that supply (Gong) for the past three years, while the City of Ballarat has also made substantial water savings."

Mr Hancock said the council had also asked the State Government to fast-track a stormwater diversion policy, its favoured long-term response to secure the lake's future.