The Kurnell desalination plant which has sat idle for the past five years may need to be switched back on if Sydney’s dam levels continue to fall.
Water levels at storages supplying the Sydney metropolitan area are sinking amid a lack of rain and rising consumption.
The total storage levels for the Sydney region are running at about two-thirds full, with the desalination plant set to be turned on to supplement the water supply when capacity drops to 60 per cent, according to WaterNSW.
The Sydney Desalination Plant was constructed in response to the worst drought in 100 years, which saw Sydney's dam levels fall to 34 per cent.
Construction of the desalination plant took three years from 2007-2010.
The first desalinated drinking water was delivered to Sydney in February 2010. The plant then ran continuously for two years, from 2010 to 2012.
When dam levels rose to 98 per cent in June 2012 the plant went offline and into Water Security Mode with the focus on maintenance and care of the plant to ensure it is ready when needed.
Veolia Water Australia operate the plant under a 20 year contract and have up to 8 months to restart the plant once the instruction to restart is given.
A WaterNSW spokesman said Warragamba Dam, the largest in the Sydney network, has dropped about a quarter in the past year to be just under 70 per cent full as of Thursday.
"All Sydney storage levels have fallen as water is used to provide for Sydney’s water supply, while record low rainfall in catchment areas [has resulted] in minimal replenishing inflows," the spokesman said.
"The absence of significant rainfall forecast and the extremely dry catchments means, unfortunately, there is little prospect of respite statewide in the short term."
Cordeaux Dam, which supplies the Illawarra region, has sunk by more than half to be just under 42 per cent full, while the larger Avon Dam has dropped by a third to be 64 per cent full.
"The Illawarra supply network has capacity to supplement the Avon storage by transferring water from Nepean Dam should it be required," the spokesman said.
July was Sydney's driest since 1995, with just 11.2 millimetres of rain collected at Observatory Hill, about one-ninth of the norm.
The extended dry spell for much of Sydney - and the rest of the state - has triggered a rise in water consumption.
In June, average daily water demand in the city was 1.455 billion litres, 10.1 per cent above the 10-year rolling average, Sydney Water said.
For the first half of 2018, water demand has totalled 297 billion litres, the most since 2003.
Average water use is also on the rise, with a per capita demand in June of 324 litres a day - the most since July 2007 towards the end of the Millenium Drought.
Gary Hurley, Sydney Water's manager for networks, said the drying conditions had led to a spike in leaks and breaks in water pipes.
Call-outs to fix leaks had been stable since about 2009 but jumped more than 50 per cent this year to 120-150 a day, compared with a five-year average, Mr Hurley said.
Cordeaux Dam
Just a stone’s throw from Wollongong sits Cordeaux Dam, which is currently a shadow of its former self.
The storage – which has a capacity of 93,640 megalitres – was just 41.9 per cent full on Thursday.
The rapidly-receding water level has left large sections of the 7.8sqkm storage exposed.
The water marks visible on the dam’s wall tell of better times – like this time last year, when Cordeaux was about 94 per cent full.
The dam – which can be accessed by the public off Picton Road – supplies water to the Camden, Campbelltown and Wollondilly council areas via the Macarthur water filtration plant.
Cataract Dam
At nearby Cataract Dam – which also supplies water to Camden, Campbelltown and the Wollondilly – the volume of water has more than halved in the past 12 months.
On Thursday, the 97,190-megalitre reservoir had 36,715 megalitres of water in it; 37.8 per cent of its capacity.
Cataract is one of the oldest dams in the Greater Sydney catchment area and the first of four dams built to collect water from the Illawarra Plateau, according to WaterNSW.
Nepean Dam
The Nepean Dam – which was at 55.6 per cent of capacity on Thursday – supplies Bargo, Thirlmere, Picton and The Oaks.
The dam – located near Bargo – forms part of WaterNSW’s Nepean system, along with the Avon, Cataract and Cordeaux dams.
The system supplies water to Sydney, as well as the Macarthur and Illawarra regions. Nepean Dam can be topped up with water from the Shoalhaven and Kangaroo rivers when required.
The supplementary water comes from Tallowa Dam, west of Nowra. The Tallowa storage is used by Shoalhaven City Council to supply water to the Nowra area.
Woronora Dam
The Woronora Dam, west of Waterfall, supplies water to residents across parts of the Sutherland Shire, as well as Helensburgh, Stanwell Park and the northern Illawarra.
The storage was the healthiest of the five Illawarra dams on Thursday, sitting at 65.1 per cent of capacity.