Cardinia Reservoir will receive the largest order of water after storage levels dropped to under 50 per cent.
The order of 125 gigalitres began flowing into the reservoir on Tuesday 11 June and will continue to be delivered progressively over the next year.
It comes after water storage levels at the reservoir were recorded at 49.8 per cent, down 8 per cent compared to the same time last year.
Despite recent rainfall, water levels are close to their lowest since 2011, when the Millennium Drought severely impacted water storages.
The order of water has come from the Victorian Desalination Plant in Dalyston, the only source of water which isn’t dependant of rainfall.
The plant can deliver up to 150 billion litres of high-quality drinking water a year.
Minister for Water Lisa Neville said the desalination plant is crucial given that Melbourne’s water demand has outstripped supply in recent years.
“Water is now flowing into our storages from the desal plant, building a buffer against the challenges of climate change and increased demand from population growth,” Ms Neville said.
“The water order underpins water security for Melbourne and surrounding regions – meaning certainty for families, businesses, sporting grounds and local communities.”
Only customers in metropolitan Melbourne pay for the desalination order, with an average of about $10 extra per household being added to water bills to supplement the latest order.
The average annual daily use of water is approximately 161 litres per day, but by adopting water efficiency measures at home and following the Permanent Water Saving Rules, it’s hoped daily usage can be reduced to 155 litres per day.
“Combining desalinated water with water efficiency measures, while investing in recycled water and storm water harvesting, all helps to secure Melbourne’s water supply for the future,” Ms Neville said.
Melbourne Water has been contacted for comment.