Western Sydney Sewer Plan Confronts 2031 Capacity Cliff

Western Sydney’s sewer network would expand by 70ML a day under new treatment plans now on exhibition, widening capacity ahead of a projected 2031 ceiling in the existing coastal system.

Sydney Water lodged a State Significant Infrastructure application—on exhibition until March 11—for a new Water Resource Recovery Facility (WRRF) within the Camellia industrial precinct near Parramatta.

Across the Greater Parramatta and Olympic Peninsula (GPOP) corridor, wastewater currently travels north via the Northern Suburbs Ocean Outfall Sewer (NSOOS) to the North Head WRRF before discharge to the ocean.

Camellia Pumping Station, which services about 250,000 people, currently contributes roughly 25 per cent of flows to North Head.

Under the proposal, up to 70ML a day would be diverted at this point for local treatment, reducing pressure on the coastal trunk sewer.

Planning documents projected housing and employment growth across the corridor to mounting pressure in the coastal network.

“Anticipated growth in housing and commercial development is expected to place pressure on existing critical assets, with the NSOOS and the North Head WRRF expected to reach capacity around 2031,” the documents said.

“The NSOOS does not have the capacity to transfer the additional wastewater generated from this growth.”

▲ The proposed Camellia water treatment plant and pipeline routes linking Parramatta River to North Head ocean outfall.

Similar servicing constraints have already slowed delivery elsewhere in NSW, with wastewater bottlenecks stalling a 15,000-home scheme in south-west Sydney.

Projected volumes would fill the coastal sewer and North Head plant to capacity. Once full, additional development could not be serviced without new infrastructure.

“GPOP is forecast to grow by about 110,000 new homes and 196,000 new jobs by 2056… therefore, the current system is inadequate to support new homes and job growth,” the documents said.

Under the proposal, wastewater diverted at Camellia would undergo advanced treatment including reverse osmosis before release into the Parramatta River near Meadowbank via a 7.6km discharge pipeline, rather than travelling to the coast for ocean outfall.

About 15km of new and upgraded pipeline infrastructure forms part of the scheme. 

Proposed works include a 2.2km transfer main linking the pumping station to the facility, a 5.2km brine pipeline reconnecting to the ocean outfall system, and pumping upgrades.

▲ North Head Water Resource Recovery Facility at Manly treats wastewater from about 1.7 million people before discharging into the ocean.

The facility would rise on a 21.41ha Sydney Water-owned site at the intersection of Colquhoun and Devon streets, Rosehill. 

The site is on a peninsula between the Parramatta and Duck rivers within the Camellia-Rosehill industrial area, a precinct flagged for renewal while retaining industrial jobs.

The site currently accommodates industrial infrastructure including the existing heritage-listed Camellia Pumping Station and associated utility operations. 

Surrounding land uses include heavy industry, Sydney Olympic Park to the east and emerging mixed-use redevelopment areas toward Parramatta CBD.

Construction was identified from 2028 to 2031, with operations targeted for 2032.

Existing coastal infrastructure would remain operational. North Head would continue to treat flows and discharge to the ocean, while Camellia would share load within the broader network.

The Scoping Report canvassed expansion at North Head and duplication of the ocean outfall transfer system as alternatives, describing those options as carrying multi-billion-dollar cost implications. 

▲ Greater Parramatta and Olympic Peninsula corridor within Sydney’s northern suburbs wastewater catchment and proposed Camellia treatment infrastructure.

It said duplication would require capital outlay estimated at around $5 billion, while the Camellia option avoided this expenditure.

The exhibition comes as the NSW Government and Sydney Water advance a separate 10-year, $3 billion wastewater upgrade program focused on Sydney’s coastal treatment network, including North Head, Bondi and Malabar.

Announced in January after debris balls—found to contain congealed fats, oils and human waste—washed up on Sydney’s eastern beaches, the program would reduce overflows and upgrade ageing ocean outfall infrastructure.

The Department of Planning, Housing and Infrastructure would assess the application before determination.