Eyre Peninsula desalination plant advances as marine works push through hard granite

The Eyre Peninsula Desalination Plant at Billy Lights Point, near Port Lincoln, is well into construction. Major equipment is installed at the plant site, the 7-kilometre transfer pipeline is built, and marine crews are installing the intake and outfall pipelines.

The one moving part is the date. Hard granite beneath the seafloor slowed the tunnel boring machine building the plant's marine tunnel, and in July 2026 SA Water said its late-2026 first-water target would need to be revised. As of SA Water's September 2026 project update, a new first-water date had not been announced.

SA Water says the change will not affect the region's drinking water security: its 2026–27 groundwater allocation is sufficient to meet customer demand until the plant is operating, and it does not expect to need water restrictions.

The essentials

The plant will supply around 35,000 SA Water customers on the Eyre Peninsula, supplementing the Uley South groundwater basin and reducing reliance on River Murray water.

The ECI actually converted

This is the most useful thing about the project for a contracting audience.

ACCIONA was awarded the Early Contractor Involvement contract in November 2023, to carry out investigations at Billy Lights Point and support SA Water in developing the detailed design. In July 2025, SA Water confirmed ACCIONA, which led the ECI phase, as the contractor to deliver the plant. McConnell Dowell signed its own contract with SA Water for the marine works, and Leed is designing and building the transfer pipeline.

Early Contractor Involvement is used widely in Australian infrastructure, but an ECI does not always end with the same contractor building the job.

Eyre Peninsula is a clean example of the model working as intended: a contractor engaged early, involved in developing the design and cost, then appointed to build it — with a revised, better-informed cost published at the point of conversion.

That the cost rose from $330 million to $470 million at conversion is not a failure of the model. It is arguably the model doing its job — producing a realistic number before main works rather than after.

The cost and schedule history

From $330 million to about $470 million is a 42 per cent increase. The government attributed it to design changes — chiefly tunnelling the marine pipelines beneath the shoreline and intertidal areas, and placing the intake and outfall in deeper water — combined with inflation. It said the extra cost would be managed within SA Water's existing state-wide capital program and would not affect customer bills.

Progress

SA Water's monthly project updates track steady progress across the site:

• Marine works (McConnell Dowell). Tunnel boring machine "Janette" arrived in Port Lincoln in February 2026 to bore a 2.5-metre-diameter tunnel, around 440 metres long, beneath the shoreline to house the intake and outfall pipes. In July 2026 SA Water said about 80 per cent of the tunnel was complete, but that granite denser than its geotechnical investigations had indicated had significantly slowed progress. SA Water said it was working with its marine contractor to speed the drive, including adjusting the machine's cutting discs and sourcing additional tunnelling support workers. By September, installation of the intake and outfall pipelines was ongoing.
• Transfer pipeline (Leed). The 7-kilometre pipeline linking the plant to the Northside Hill tanks was completed in April 2026 and has been tested.
• The plant (ACCIONA). ACCIONA's mechanical and electrical team began its structural, mechanical and piping installation package in March 2026. In September SA Water reported that major equipment had been installed, electrical works were nearing completion, and water storage and treatment infrastructure was advancing.

Marine exclusion zones at Billy Lights Point remain in place until 31 January 2027.

What to watch

1. The revised first-water date, which SA Water said it would set once it could gauge the boring machine's progress through the remaining granite.
2. Commissioning. As with every water and rail project in this series, process commissioning follows construction completion and is not the same event as the plant producing water.
3. Whether $470 million holds through completion.
4. SA Water's broader capital program, of which this is one of several commitments.

Published 1 September 2026 · Updated 4 October 2026