Alkimos Seawater Desalination Plant

Alkimos Seawater Desalination Plant

The WA Government has proposed construction of a new desalination plant to be delivered by WA Water Corporation. The desalination plant will be located in Alkimos, north of Perth and adjacent to an existing wastewater treatment plant. The full scope of the project would be delivered in two stages, with only the 50 billion litre stage one currently confirmed.  

Included in the scope of Stage One is:

  • desalination plant with a 50 billion litre annual capacity
  • ocean intake pipeline below the seabed
  • an ocean discharge pipeline below the seabed to transport brine from the plant
  • a 34-kilometre pipeline to transport drinking water to Wanneroo Reservoir

WA Water Corporation is expected to secure a Power Purchase Agreement for up to 400 megawatts of renewable wind energy to power the Alkimos Seatwater Desalination Plant, as well as its existing desalination plant at Kwinana and Binningup.

Key Dates

Jun 2022 Project Announcement
Dec 2023 Preferred Bidder Selection - Stage One Design and Construction
Apr 2024 Preferred Bidder Selection - Operations
2028 Expected construction completion: Stage One

Funding contributions

User charges


Procuring Agency: WA Water Corporation
Successful Tenderer: Consortium of ACCIONA Agua Australia, ACCIONA Construction and Jacobs Group Australia. The companies will form the Northern Water Partnership (NWP)
Procurement note:

The consortium was previously known as the Northern Water Partnership (NWP).


May 2022 The 2022-23 WA Budget announced WA Water Corporation would retain its forecast FY2021-22 dividend payment of $1.4 billion in the 2021-22 Budget to instead contribute to funding a new desalination plant.
Jun 2022 The WA Government announced the project and confirmed the new desalination plant would be located in Alkimos, with a proposed scope of 100-billion-litres per year.
May 2023 The WA Government allocated $65 million towards early enabling works in the 2023-24 Budget.
Nov 2023 The project received environmental and planning approvals from the Federal Department of Climate Change, Energy, the Environment and Water, and the WA Environmental Protection Agency.
Dec 2023 The WA Government confirmed $2.8 billion in funding to the project.
Dec 2023 A consortium of ACCIONA Agua Australia, ACCIONA Construction and Jacobs Group Australia was selected as the preferred proponent to design, build and operate Stage 1 of the Desalination Plant. Subject to further negotiations, the consortium will form an alliance to be known as the Northern Water Partnership (NWP).
Apr 2024 The WA Government announced that the desalination plant will be operated by Northern Water Partnership alongside WA Water Corporation, together forming Alkimos Seawater Alliance. The operations contract will be for a minimum of 10 years from the project's completion.
May 2024 The 2024-25 WA Budget announced WA Water Corporation would retain its forecast FY2023-24 dividend payment of $766 million to instead contribute to its asset investment program, including $656 million for the Desalination Plant. WA Water Corporation allocated $597 million towards the project's program of work in FY2024-25.
Estimated Total Cost
Water & Sewerage
Procurement approach
Alliance |
Western Australia |
Project pages
WA Water Corporation