Illawarra Water Security project

Illawarra Water Security project

As New South Wales continues to experience one of the worst droughts on record, WaterNSW has been progressing investigations on a range of infrastructure options to secure water supply across the Sydney Basin and the Illawarra.

About the project

The NSW Government’s Metropolitan Water Plan 2017 requires WaterNSW to investigate drought supply options when Greater Sydney total dam storage levels reach 60 percent.

Since February 2019, when total dam storage levels declined to 60 percent, the Illawarra Water Security project has been investigating options to access 67 gigalitres (GL) of deep water stored in Lake Avon. Accessing this deep water will extend the available water supply by up to two years for the Illawarra Region and will increase long term yield by 5 GL (5 billion litres) per year.

The project involves a deep water pumping station at Avon Dam and a pipeline to transfer water to the existing Illawarra Water Filtration Plant.

Accessing the deep water in Avon Dam was first considered during the Millennium drought and deep water access projects have already been completed at Warragamba and Nepean dams.

WaterNSW, as the owner and operator of Avon Dam, will continue to inform stakeholders about the project as the planning phase continues. Subject to approvals, the project could be operational by early 2022.

Project timeline

  • May 2019 – Preliminary planning started
  • August 2019 – Early investigation, preliminary design, stakeholder engagement commenced
  • October 2019 to Mid 2020 – Detailed planning and business case development for submission to Infrastructure NSW
  • Mid 2020 – Construction to begin (subject to approvals)
  • Early 2022 – Construction to be completed

For more information on the planning process, visit Infrastructure NSW.

Project Fact Sheet

For more information, see our project fact sheet (PDF, 350.61 KB).

Frequently Asked Questions

Avon Dam is located about 100 kilometres south of Sydney and is the largest of the four dams constructed to collect water from the Illawarra Plateau. Created by damming the Avon River and completed in 1927, Avon Dam is the main water supply source for the Illawarra region. It is one of the 10 major dams in the Sydney Metropolitan Water Supply Scheme. It is the second largest reservoir after Warragamba Dam.

Deep water is water which is currently inaccessible to the water supply system. Usually, it is below the lowest outlet point in a dam from where water can be extracted, or below the level where gravity can draw the water from the dam.

Yes. In the Millennium Drought, the Metropolitan Water Plan identified deep water access as a drought response measure for the Sydney basin. Deep water pumping stations were installed at Nepean and Warragamba Dams to increase accessible water supply.

The project involves a deep water pumping station at Avon Dam and a pipeline to transfer water to the existing Illawarra Water Filtration Plant.

This will make available water which currently cannot be accessed thus increasing the volume of accessible water. This will improve water security and extend the water supply for the Illawarra region.

The project once constructed will provide access up to an additional two years of water supply for the Illawarra region.

Thorough investigation and assessment processes will be undertaken to ensure the project has minimal impacts to the environment. On-site environmental investigations began in September 2019.

Avon Dam is remotely located and surrounded by land managed by WaterNSW and National Parks and Wildlife Services.

Privately owned properties will not be impacted by the project.

The WaterNSW team will liaise closely with stakeholders as the project develops.

Avon Dam is a heritage structure and is protected under the Heritage Act 1977. This project will be planned to minimise construction and operational impacts to the dam wall and heritage structures.

Water quality tests show the quality of the water in deep storage is good. Water in Avon Dam is naturally mixed and aerated. These natural and mechanical processes will aim to keep the quality of water in the dam consistent from top to bottom.

Water quality at this level will be monitored to ensure it meets the water filtration plant requirements.

WaterNSW is committed to providing stakeholders with clear, concise and timely information about the Illawarra Water Security Project and welcomes feedback.

If you would like any more information on this project, please contact WaterNSW.

This project is currently in the preliminary planning phase and a business case has been submitted to Infrastructure NSW.

Contact us

If you would like any more information about this project please contact WaterNSW.


Monday 30 March
2,152,414 ML
2,596,150 ML
9,007 ML
1,287 ML
9,481 ML
Monday 30 March