Water Restrictions May Not Fix Our Drinking Problems This Time

Dam levels are dropping fast, and water restrictions are imminent, as a crippling drought continues to grip the country.

The last time Sydney enacted water restrictions, it changed the city's relationship with the vital liquid.

It was 2003, and the Millennium Drought -- which devastated communities across most of southern Australia between 2000 and 2010 -- had water storage levels plummeting.

The city eventually found itself on the highest level of restriction, amid what was the country's longest dry spell in history.

It led to a spate of water efficiency measures still in place today -- you would be hard-pressed to find a Sydney golf-course not using recycled water for irrigation these days.

READ MORE: 'When Is This Going To End?': The First Responders Battling Drought

Now, as the severe NSW drought continues, the harbour city is preparing for water restrictions once again.

The current depletion rate and weather conditions mean Sydney should expect formal water restrictions to be enforced "soon if there is no rain", state water minister Melinda Pavey told 10 daily.

While "soon" might sound vague, the city's dams give us a countdown.

Sydney's water storage levels currently sit at 53.8 per cent, and the first level of water restrictions will kick in when it hits 50. Levels have been dropping an average of 0.4 per cent, so we can expect the 50 percent mark to be hit in around 10 weeks, or near the start of August.

Available water storage, 1998-now. Image: Water NSW

It's a story of steeply sloping graphs, with water levels nearly half what they were just 12 months ago.

"Greater Sydney is in drought and dam levels are dropping faster than they have in decades," a spokesperson for Sydney Water said in a statement.

"Over the last two years, dam levels have dropped faster than the average rate during the Millennium drought."

But while water storage levels have continued to decline, so has the water use of your average Sydney resident.

"Today, the average Sydneysider uses around 200 litres of water per person per day," a spokesperson for Sydney Water told 10 daily.

"Before the Millennium drought, the per person per day figure was nearly 250 litres."

How much water we use in Greater Sydney. Image: NSW Government

The figures have experts concerned that planned water restrictions won't be as effective as last time, because people have already greatly changed their behaviour -- so restricting water won't do as much as it once did.

"We act differently now and we have different infrastructure," said Stuart Khan, professor in the University of NSW's School of Civil & Environmental Engineering, told 10 daily.

"All of those measures relieved a lot of pressure off the drinking water supply and we never went back. What we are concerned about is that we've now picked the low-hanging fruit, we've taken those easy steps... so to be able to save more litres will hurt a lot more."

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As per the state government's 2017 Metropolitan Water Plan, the first level of water restrictions will mean rules which are currently voluntary -- such as not hosing driveways and paths, and only allowing watering of gardens before 10am and after 4pm -- will become compulsory.

Goulburn's Pejar Dam, in 2005. Image: AAP

In January, Kurnell's desalination plant was also switched, on as dam levels dipped below 60 per cent.

When up and running at full capacity it will provide about 15 per cent of Sydney's drinking water. This is expected to happen in August, the Sydney Morning Herald reports, which is a month ahead of schedule.

READ MOREThe Drought Isn't Over Just Because The Media Coverage Is

Though considered the city's first line of defence, the desalination plant is no silver bullet.

"Even if you had it running full bore all of this year, that extra 15 per cent coming into our waterways really would not turn around the trend we've seen," Khan said.

"While the desalination plant was turned off, we used to refer to it as Sydney's 'insurance policy', which I think gives people the sense it's there when you need it and it will solve all of our problems.

"But it really won't."

Desalination plant employees demonstate the loading of a Reverse Osmosis Filter at the Desalination Plant in Sydney. Image: AAP

Elsewhere in the state, some towns are on level two, three or even four of water restrictions, while the Bureau of Meteorology doesn't predict any big future rainfall.

Despite the impending challenges for Sydneysiders, water minister Pavey said it is important to keep things in perspective.

"I think it’s extremely important that Sydney residents understand and recognise that 99 per cent of our state is in drought, with regional and rural communities facing the brunt," she said.

"Families, communities, living in these regions are enduring one of the most severe droughts on record. These are people’s livelihoods at stake."

You can find more information on Sydney's Water Wise Rules here.