UP TO one third of Bendigo’s water is evapoating into thin air each week.

The revelation comes as Coliban Water considers even tougher water restrictions for Bendigo, Castlemaine and Kyneton.

In the past seven weeks Coliban Water has sent an average of 400 megalitres to Bendigo from its Malmsbury Reservoir.

However, the city has been using an average of only about 220 megalitres.

While some of that water is sent to priority irrigators and some lost in the system, the majority of it is lost to evaporation.

Latest figures reveal the equivalent of about four days worth of water is evaporating each week.

For the week ending December 15, almost 115 of the 367 megalitres released to Bendigo’s Sandhurst Reservoir evaporated.

One week earlier, about 110 megalitres was lost, however about 548ML was released.

Alarmingly that week, 72 megalitres was unaccounted for, a figure that usually sits around the 24ML mark. Late last year, Coliban Water announced it would use technology to try and solve the evaporation problem at the Bendigo end.

The authority plans to use a product called WaterSavr at Sandhurst Reservoir that places a thin film on the water, however that is yet to happen.

The evaporation figures cast doubt on Coliban’s claims there is enough water for the city until the Goulburn-to-Lake-Eppalock pipeline comes on board.

However acting chief executive Neil Burns assured locals the water would not run out.

“As you get into the colder months evaporation decreases,” he said.

“The balance is not constant. There is higher losses in the summer than there are in the winter.

“When we look at what the losses are likely to be in the winter, what gets us from July to September is probably the fact we are not losing as much at that time of the year as we are losing now.

“You can’t apply the same loss rate in the summer to the winter.”

Meanwhile, Coliban chief executive Geoff Michell told ABC Radio last week the authority may have to consider tougher water restrictions if central Victorians didn’t start using less water.

Mr Burns said there were a number of avenues open to Coliban, but said residents would not be compulsorily limited to a set number of litres per day.

“We might turn around and say all pool top-ups are banned,” he said.

“I don’t know if we would do it, but we have to think seriously at air-conditioners. They use a reasonable amount.

“It’s one of those balancing things.

“Can we afford to have them run continuously, or do we say you can only run them so many hours a day?”

Coliban will also step up its campaign to encourage people to use no more than 150 litres of water each per day.