Frequently Asked Questions

Is the Sydney Desalination Plant operational at the moment?

The plant continues to be available to produce water if required to assist in maintaining water supplies to the Sydney metropolitan area.

This means the plant continues to produce a small amount of water and can be restarted immediately, if needed.

The extension of our availability recognises that the Sydney Desalination Plant has always been and will continue to be, an essential component of Sydney’s water management and an integral part of Sydney’s water resilient future.

How much water is the plant producing currently?

The plant produces a small amount of water in its current operating mode, and can be restarted immediately, if needed.

The plant played a key role in ensuring drinking water for over two million Sydney households during the 2019-20 drought when dam levels fell to nearly 40 per cent.

At that time, the plant at full capacity was producing about 15 per cent of Sydney’s water needs.

How much does the Desalination Plant Cost?

The cost for operating and maintaining the Sydney Desalination Plant are determined and regulated by a NSW independent regulator (IPART) and charged by Sydney Water to its customers.

These prices are fully transparent and can be found on links on this website under the Regulatory section and also on the IPART website.

For further information on costs of water please contact Sydney Water.

Why do we have a desalination plant?

Sydney’s Desalination Plant is one effective way of securing Sydney’s water supply against the effects of climate change, population growth and drought. Desalination is part of the Metropolitan Water Directorate’s Water 2017 Metropolitan Water Plan, along with dams, recycling and water efficiency programs. The plan secures a sustainable and affordable water supply for greater Sydney. The Sydney Desalination Plant is powered by 100% renewable energy and can supply up to 250 million litres of water a day, which is approximately 15% of Sydney’s water needs. The water provided by the desalination plant benefits all water users in Sydney either directly or indirectly because it allows more water to be left in the dams, which means a more secure water supply for Sydney.

Desalination turns seawater into drinking water. Many countries around the world use desalination as a way of creating a more reliable source of water that does not depend on rain.

Why is desalination important?

Desalination is important because it is the only non rainfall dependent direct source of drinking water. Sydney has highly variable rainfall. The Sydney Desalination Plant ensures that Sydney has a secure source of drinking water for now and in the future. Along with dams, recycling and water efficiency programs, desalination can help protect against the impacts of drought, population growth and the effects of climate change.

Who do we supply?

Sydney Desalination Plant can supply water to up to 1 .5 million people south of Sydney Harbour and as far west as Bankstown, as part of all of their water supply.

Sydney Water use a variety of sources (including various dam, The Nepean Hawkesbury River and the Sydney Desalination Plant) to supply customer needs. Where your water comes from changes, depending on demand and on where in Sydney you live.

If you live in the green-shaded area on this map, you may receive water from the dams, the desalination plant or a combination of both. The proportion of water from the plant will change throughout the day due to supply and demand variations.

Everyone will benefit from desalination because it allows more water to be left in the dams, which means a more secure water supply for Sydney.

What is the process of desalination?

Desalination is the process of removing dissolved salts and other particles from seawater. Sydney Desalination Plant is powered by 100% renewable wind energy and uses reverse osmosis to extract fresh water from seawater. The plant contains over 36,000 reverse osmosis membranes which, under pressure, filter out particles and salts, so that fresh water can pass through, leaving the seawater concentrate to be returned to the ocean.

Pre-treatment of seawater

Seawater flows into the plant under gravity, through a large pipe. Large screens are used to filter out debris down to 3 milimetres in diameter then the Seawater is filtered through sand and coal to remove even smaller particles

Desalination – Reverse osmosis

The very clean seawater, is then forced at high pressure through thousands of reverse osmosis membranes, which act as very fine filters, to remove dissolved salts and other particles. Fresh water is extracted and seawater concentrate is left behind. Approximately 42% of the seawater becomes drinking water.

Drinking water

The fresh water produced by the Sydney Desalination Plant is treated to meet the Australian Drinking Water Guidelines. Fluoride is added, as is done with all of Sydney’s water.

The drinking water then travels through an 18 kilometre pipeline to join the Sydney Water supply network at Erskineville. It can supply up to 1.5 million people south of Sydney Harbour and as far west as Bankstown.

Seawater concentrate

The remaining seawater concentrate is about twice as salty than the ocean. It is returned through a large pipe that lies beneath the seabed. The seawater is dispersed using specially designed diffusers which return the seawater concentrate to normal salinity within 50-75 metres from the outlet point.

What happens to the brine that comes from running desalination?

Approximately 58% of the intake seawater is returned to the ocean as seawater concentrate or brine. The seawater concentrate is about twice the salinity warmer than the ocean.

The seawater concentrate flows through the outlet tunnel and is dispersed deep in the ocean through specially designed diffuser nozzles attached to the outlet risers. The seawater concentrate returns to normal salinity within 50-75 metres of the outlet.

How much energy does the plant use?

The Sydney Desalination Plant is powered by 100% renewable wind energy and requires roughly 38 Megawatts at full production. The energy it consumes is equivalent to the energy consumed by a domestic fridge if all of the water used in the household was supplied from our desalination plant.

What is the impact on the environment?

SDP places a high priority on minimising any environmental impacts – both on land and in the water. To support this, SDP has put in place one of the most stringent marine environment monitoring programs of its kind. The marine environment was monitored for three years before construction and for three years after commissioning.

The Marine and Estuarine Monitoring Program (MEMP) has also been a strong focus of the SDP. Research has shown that, once discharged to the ocean, the seawater concentrate returns to ocean salinity within 50 – 75 metres from the outlet. This is called the near field mixing zone. It has been found that there are no significant impacts on seawater quality or aquatic ecology from the seawater concentrate beyond the near field mixing zone and minimal impact within near field mixing zone.

On land , a third of the plant site at Kurnell has been kept as a conservation area. This area is protected and native species of flora and fauna are regularly monitored. This includes a program to survey the numbers of grey headed flying foxes and green and golden bell frogs in the area.

The Capital Wind Farm at Bungendore produces more than enough energy to offset the power needs of the desalination plant and is an environmentally friendly way to supply the power needs of the Sydney Desalination Plant.

How much carbon dioxide is emitted by the energy needed to power the plant at full production?

The Sydney Desalination Plant uses 100% green power purchased from a wind farm company as an offset for all energy consumed on site at all times, even when in preservation mode. Therefore, the electrical energy footprint of the process is zero carbon emissions.

How does the desalinated water taste?

Sydney Desalination Plant water is treated to taste the same as Sydney’s other drinking water sources. Like dam water, water from the desalination plant is treated to meet Australian Drinking Water Guidelines, which makes it among the best in the world.

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