North West Treatment Hub

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We’re building a more resilient wastewater system

Sydney’s north west is growing rapidly, with the region’s population expected to double by 2056. To enable Sydney Water to adaptively respond to growth, Sydney Water is delivering the North West Treatment Hub Program, which includes a suite of upgrades to cater for growth in the area.

The North West Treatment Hub includes three treatment facilities in the region – Castle Hill, Rouse Hill and Riverstone Water Resource Recovery Facilities (WRRFs). We are upgrading these WRRFs to ensure we can continue to provide an efficient wastewater system to cater for this growth and keep our waterways clean.

Sydney Water has partnered with John Holland, Stantec and KBR to form the North West Hub Alliance (NWHA).

The NWHA will deliver upgrades at Riverstone and Rouse Hill WRRFs to support an extra 45 megalitres of wastewater each day. That’s equivalent to 18 Olympic sized swimming pools!

Work on the North West Treatment Hub is happening under three programs:

We’re building a more resilient wastewater system

Sydney’s north west is growing rapidly, with the region’s population expected to double by 2056. To enable Sydney Water to adaptively respond to growth, Sydney Water is delivering the North West Treatment Hub Program, which includes a suite of upgrades to cater for growth in the area.

The North West Treatment Hub includes three treatment facilities in the region – Castle Hill, Rouse Hill and Riverstone Water Resource Recovery Facilities (WRRFs). We are upgrading these WRRFs to ensure we can continue to provide an efficient wastewater system to cater for this growth and keep our waterways clean.

Sydney Water has partnered with John Holland, Stantec and KBR to form the North West Hub Alliance (NWHA).

The NWHA will deliver upgrades at Riverstone and Rouse Hill WRRFs to support an extra 45 megalitres of wastewater each day. That’s equivalent to 18 Olympic sized swimming pools!

Work on the North West Treatment Hub is happening under three programs:

  • Castle Hill Water Resource Recovery Facility upgrade starting soon

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    The compliance upgrade work at Castle Hill is now underway and will take up to two years to complete. This work will include:

    • replacing and upgrading equipment to improve water quality, and odour, and reduce noise
    • new facility buildings
    • minor extensions to the current fence line
    • an additional treated water discharge main to Cattai Creek
    • a new high voltage electricity line to connect into the facility.

    Our work crews and trucks will access the facility from Wrights Road. Drawbridge Place will be used as a secondary access route.

    While most of our work will be within the plant boundary, we will be making some adjustments to the walking track along the western boundary (nearest to Wrights Road) to protect the safety of walkers and to make room to complete our work. During the project, a new walking track will be in place adjacent to the existing track. Detour signage will be in place to guide pedestrians and cyclists around the site.

    Our work hours are between 7am and 6pm, Monday to Friday and 8am to 1pm on Saturdays. Where work may be required outside of these hours, we will notify affected residents before the work.

    Read our latest community update here.

  • REF Decision Report has been published

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    The Decision Report from the latest Review of Environmental Factors (REF) has now been published and can be viewed and downloaded from the Document Library.

    This Decision Report:

    • considers the comments raised in the submissions
    • identifies whether any new mitigation measures or changes to existing mitigation measures are required
    • recommends whether Sydney Water should proceed with the proposal.

    We would like to again thank everyone who provided their feedback on the REF and attended an information session or contacted us regarding the North West Treatment Hub.

  • Next steps

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    In August 2022, we displayed the Review of Environmental Factors for proposed work to connect three treatment plants, with two pipelines and upgrades at two plants. During this time, we held information sessions, in-person and online, to give the community an opportunity to speak to us and ask questions.

    Thank you to everyone who attended an information session, contacted us and provided feedback.

    We are now considering the issues raised. Our next step will be to publish a Decision Report in the coming months, outlining these submissions and our responses to the issues raised.

  • Come along to an information session

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    CLOSED: This discussion has concluded.

    We're holding information sessions to give the community an opportunity to speak to the project team and answer any questions about the latest Review of Environmental Factors (REF) for the North West Treatment Hub.

    Two online information sessions are planned:

    • Thursday 11 August, 5.30 pm to 6.30 pm

    • Tuesday 16 August, 10 am to 11 am

    We will also be holding a face-to-face information session, for community to drop-in and meet the project team and ask questions:

    • Saturday 13 August, 9.30 am to 12 pm

    This information sessions will be held at Vinegar Hill Library, Rouse Hill Town Centre (Town Centre, 29 Main St, Rouse Hill NSW 2155).

  • Check out the project’s interactive map

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    CLOSED: This discussion has concluded.
    supporting image

    We’re planning to build two pipelines, connecting three of our plants. You can now view the pipelines on an interactive map, allowing you to zoom in closer to the sections of our work that are near you.

    HERE, you can view:

    • 10.2 km pipeline, connecting Castle Hill and Rouse Hill Water Recycling Plants

    • 6.3 km pipeline, connecting Rouse Hill Water Recycling Plant to Riverstone Wastewater Treatment Plant

    • Our proposed access points from local roads, to reach the pipeline corridors

    • Trenchless sections of pipelines, including the entry and exit pits

    • Rouse Hill Water Recycling Plant and Riverstone Wastewater Treatment Plant, where upgrades are planned.

    For more information about the scope of the work proposed and the potential impacts, see the Review of Environmental Factors (REF) in the Document Library.

  • We’re not the only project supporting healthier waterways!

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    CLOSED: This discussion has concluded.
    supporting image

    Our North West Treatment Hub project is just one of the ways Sydney Water is supporting healthier creeks and local waterways in the Hills Shire. Sydney Water is proud to partner with the Cattai Hills Environment Network and Western Sydney University in a study to monitor the platypus populations across the Cattai Creek catchment area.

    The platypus is notoriously shy and difficult to spot in the wild. To know where platypuses are living in Sydney’s North West, the Cattai Hills Environment Network’s volunteers take water samples across the Cattai Creek catchment area. In June this year, with Sydney Water’s support, the monitoring program was able to double the number of sites sampled, from 18 to 36 sites. Extending the number of sample sites helps provide a better picture of local waterway health and the health of the local platypus population. Sydney Water’s lab teams have developed a testing method to provide vital information on platypus numbers from the water samples collected.

    Recently, this important monitoring program was featured on ABC news. For more information:

    Read: Sydney Water media release

    Watch: ABC news report.

    Visit: Cattai Hills Environment Network

  • REF now on display

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    CLOSED: This discussion has concluded.

    We're planning to start work focused on improving the water quality to local waterways around Castle Hill and Rouse Hill Water Recycling Plants. This work will ensure the reliability and resilience of our operations.

    We have prepared a Review of Environmental Factors (REF), guided by the Environmental Planning and Assessment Act 1979. The REF looks at all the potential benefits and environmental impacts of the project as we build it and once it's up and running. The REF needs to cover all scenarios, even though there will be opportunities to improve or even eliminate some of these impacts as we continue to fine-tune this project. It includes:

    • the background to this project,
    • proposed construction activities, including work locations within the Castle Hill and Rouse Hill Water Recycling Plants, and
    • potential environmental impacts, including traffic and access.


    The REF is on display from Monday 16 August to Sunday 5 September 2021.

    You can view and download the REF from the Document Library.

    The next step is for you to let us know what you think.

    You are invited to make a written submission by Sunday 5 September 2021 via email to NorthWestTreatmentHub@sydneywater.com.au

Page last updated: 05 Mar 2025, 01:57 PM